Fibrinolytic variables and cardiovascular prognosis in patients with stable angina pectoris treated with verapamil or metoprolol. Results from the Angina Prognosis study in Stockholm

Expanding Indications of Nonvitamin K Oral Anticoagulants Beyond Nonvalvular Atrial Fibrillation and Venous Thromboembolism: A Review of Emerging Clinical Evidence

Direct oral anticoagulants (DOAC) have emerged as a new therapy for patients who need and can tolerate oral anticoagulation. DOACs were initially approved for nonvalvular atrial fibrillation (NVAF) and treatment for deep vein thrombosis (DVT) and pulmonary embolism (PE). Ease of administration, no requirement of bridging with other anticoagulants, and less frequent dosing have made DOACs preferable choice for anticoagulation. Studies are showing promising results regarding use of DOACs beyond the common indications. Studies have been done to show the potential benefit of DOACs in valvular atrial fibrillation, heart failure, acute coronary syndrome, stroke, and peripheral arterial disease. Data have shown safety as well as comparable bleeding incidences with DOACs compared to vitamin K antagonist anticoagulants. Naturally interest is growing to see the use of DOACs apart from the NVAF, DVT, or PE. Authors have highlighted various study results to show the potential beneficial role of DOACs in the above-mentioned situations.

Gene expression of fibrinolytic markers in coronary thrombi

BACKGROUND

The fibrinolytic system plays an important role in coronary artery atherothrombosis, and especially circulating plasminogen-activator inhibitor (PAI) type 1 (PAI-1) associates with increased mortality, infarct size and heart failure in patients with myocardial infarction (MI). In a cross-sectional study, we aimed to study whether genes encoding tissue plasminogen activator (tPA), urinary-type plasminogen activator (uPA), PAI-1 and PAI-2 are expressed in coronary thrombi from acute ST-elevation MI (STEMI) patients. Any relations to myocardial injury measured by peak troponin T, time from symptom onset to Percutaneous Coronary Intervention (PCI), and to different cell types present in the thrombi were also explored.

METHODS

Intracoronary thrombi were aspirated from 33 STEMI patients treated with primary PCI. The thrombi were snap-frozen for gene expression analyses, relatively quantified by RT PCR. Peripheral blood samples were drawn. Correlations were performed by Spearmans rho.

RESULTS

The genes were present in 74-94% of the thrombi. Median peak troponin T was 3434 μ/L and median ischemic time 152 min. There were no significant correlations between the measured genes and troponin T, or ischemic time. Genes encoding tPA, u-PA, PAI-1 and PAI-2 all correlated significantly to the presence of monocytes/macrophages (CD68) in the thrombi (p = 0.028, p < 0.001, p = 0.003, p < 0.001). PAI-1 and PAI-2 also correlated to endothelial cells (CD31) (p = 0.002, p = 0.016). uPA associated with neutrophil granulocytes (CD 66b) (p = 0.019).

CONCLUSION

Genes encoding tPA, uPA, PAI-1 and PAI-2 were highly expressed in human coronary thrombi from STEMI patients, indicating fibrinolytic regulators playing active roles in the thrombi, although not related to myocardial injury. All markers related to the presence of monocytes/macrophages, indicating connection to local inflammatory cells.

TRIAL REGISTRATION

The study is registered at clinicaltrials.gov with identification number NCT02746822 .

Cardiovascular-renal complications and the possible role of plasminogen activator inhibitor: a review

Since angiotensin increases the expression of plasminogen activator inhibitor (PAI), mechanisms associated with an actively functioning renin–angiotensin–aldosterone system can be expected to be associated with increased PAI-1 expression. These mechanisms are present not only in common conditions resulting in glomerulosclerosis associated with aging, diabetes or genetic mutations, but also in autoimmune disease (like scleroderma and lupus), radiation injury, cyclosporine toxicity, allograft nephropathy and ureteral obstruction. While the renin–angiotensin–aldosterone system and growth factors, such as transforming growth factor-beta (TGF-β), are almost always part of the process, there are rare experimental observations of PAI-1 expression without their interaction. Here we review the literature on PAI-1 and its role in vascular, fibrotic and oxidative injury as well as work suggesting potential areas of intervention in the pathogenesis of multiple disorders.

Urban air pollution increases plasma fibrinogen and plasminogen activator inhibitor-1 levels in susceptible patients

BACKGROUND

The cardiovascular effects on fibrinolytic activity by urban air pollution are still unknown.

METHODS

Paired fasting blood samples during high and low air pollution days in Taipei were taken from a panel of 49 patients with coronary heart disease or multiple risk factors to study their fibrinolytic and inflammatory response to urban air pollution. Paired t-tests and mixed-effects models were used to determine the air pollution effects.

RESULTS

Patients' plasma plasminogen activator inhibitor-1 levels were significantly increased when hourly concentrations of particulate matter with diameters less than 10 microm (PM10) were greater than 100 microg/m during the period 0800 to 1800 h.

CONCLUSION

Urban air pollution has an adverse effect on plasma fibrinolytic function in a susceptible population.

Effect of Recombinant Human Growth Hormone and Rosiglitazone for HIV-Associated Abdominal Fat Accumulation on Adiponectin and other Markers of Inflammation

BACKGROUND/OBJECTIVE

In a previous report of HIV-infected patients with fat redistribution, we found that recombinant human growth hormone (rhGH) therapy reduced visceral adipose tissue (VAT) but increased insulin resistance, and that the addition of rosiglitazone reversed the negative effects of rhGH on insulin sensitivity. In this study, we sought to determine the effects of rhGH and rosiglitazone therapy on an array of inflammatory and fibrinolytic markers.

METHODS

72 patients with HIV-associated abdominal obesity and insulin resistance were randomized to treatment with rhGH, rosiglitazone, the combination of rhGH and rosiglitazone, or placebo for 12 weeks. Subjects with plasma and serum samples available at weeks 0 (n=63) and 12 (n=46-48) were assessed for adiponectin, C-reactive protein, homocysteine, interleukin-1, interleukin-6, tumor necrosis factor alpha, interferon gamma, fibrinogen, plasminogen activator inhibitor-1 antigen, and tissue plasminogen activator antigen.

RESULTS

Treatment with both rosiglitazone alone and the combination of rosiglitazone and rhGH for 12 weeks resulted in significant increases in adiponectin levels from baseline. Adiponectin levels did not change significantly in the rhGH arm alone . There were no significant changes in the other biomarkers among the different treatment groups.

DISCUSSION

In this study of HIV-infected patients with altered fat distribution, treatment with rosiglitazone had beneficial effects on adiponectin concentrations, an effect that was also seen with a combination of rosiglitazone and rhGH. RhGH administration alone, however, did not demonstrate any significant impact on adiponectin levels despite reductions in VAT.

Effect of obesity on acute hemostatic responses to live-fire training drills

The objective of this study was to evaluate the impact of obesity and firefighting activities on coagulation and fibrinolytic activity in relatively young, apparently healthy firefighters. Firefighters performed simulated firefighting activities for 18 minutes in a live-fire training structure. Blood samples were obtained at baseline, before firefighting, and within a few minutes of completing the activity. Nearly all markers of coagulation and fibrinolytic activity increased immediately after firefighting with an overall shift toward a procoagulatory profile. Obese firefighters exhibited lower levels of tissue plasminogen activator activity (0.98 vs 0.63 IU/ml) and higher levels of plasminogen activator inhibitor-1 activity (2.2 vs 4.5 ng/ml) at baseline compared with normal-weight firefighters, suggesting that fibrinolytic activity was lower in obese firefighters. There were few interactions between body mass index and firefighting activity, thus our findings suggest that obese firefighters did not exhibit a greater procoagulatory response to live firefighting compared with normal-weight firefighters. Acute live firefighting produced increases in both fibrinolytic and coagulatory responses; although obesity was associated with a reduced fibrinolytic profile at baseline, the changes produced by acute firefighting were similar in obese and nonobese firefighters.

β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

Bradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and non-stimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

Validation of an immunoassay to measure plasminogen-activator inhibitor-1 concentrations in human saliva

Introduction:

We have previously shown that the concentrations of D-dimer are significantly elevated in saliva compared with plasma. Saliva offers several advantages compared with blood analysis. We hypothesised that human saliva contains plasminogen activator inhibitor-1 (PAI-1) and that the concentrations are not affected by the time of saliva collection. The aim was to adopt and validate an immunoassay to quantify PAI-1 concentrations in saliva and to determine whether saliva collection time has an influence in the measurement.

Materials and methods:

Two saliva samples (morning and afternoon) from the same day were collected from healthy subjects (N = 40) who have had no underlying heart conditions. A customized AlphaLISA® immunoassay (PerkinElmer®, MA, USA) was adopted and used to quantify PAI-1 concentrations. We validated the analytical performance of the customized immunoassay by calculating recovery of known amount of analyte spiked in saliva.

Results:

The recovery (95.03%), intra- (8.59%) and inter-assay (7.52%) variations were within the acceptable ranges. The median salivary PAI-1 concentrations were 394 pg/mL (interquartile ranges (IQR) 243.4–833.1 pg/mL) in the morning and 376 (129.1–615.4) pg/mL in the afternoon and the plasma concentration was 59,000 (24,000–110,000) pg/mL. Salivary PAI-1 did not correlate with plasma (P = 0.812).

Conclusions:

The adopted immunoassay produced acceptable assay sensitivity and specificity. The data demonstrated that saliva contains PAI-1 and that its concentration is not affected by the time of saliva collection. There is no correlation between salivary and plasma PAI-1 concentrations. Further studies are required to demonstrate the utility of salivary PAI-1 in CVD risk factor studies.

Peptidergic regulation of plasminogen activator inhibitor-1 gene expression in vivo

BACKGROUND

The mechanisms by which PAI-1 biosynthesis is altered during stress have not been fully elucidated. Studies suggest a major role for neuro-peptidergic modulation of the stress response by PACAP (pituitary adenylate cyclase-activating polypeptide), a member of the VIP/secretin/glucagon family.

OBJECTIVE

We tested the hypothesis that PACAP regulates PAI-1 biosynthesis during stress in vivo.

METHODS

PAI-1 gene expression was monitored by RT-PCR in adrenal glands harvested from C57BL/6J mice that were unstressed, or subjected to restraint stress for 2 h, or treated with PACAP.

RESULTS

PAI-1 mRNA expression was markedly increased in adrenals from stressed mice. Restraint stress resulted in much smaller increments in adrenal tPA mRNA, suggesting that local adrenal tPA/PAI-1 biosynthetic balance is markedly altered by stress. The observed increases in PAI-1mRNA during stress were substantially blunted (55 ± 4%, P < 0.001) by pretreatment with the specific PACAP receptor antagonist, PACAP6-38, compared with pretreatment with vehicle. Administration of the agonist PACAP1-38 alone resulted in a dose-dependent increase in tissue PAI-1 mRNA. PACAP1-38 administration also resulted in substantial increases in plasma PAI-1 antigen and active PAI-1 concentrations that were significantly greater in male mice than in female mice.

CONCLUSIONS

We conclude that adrenal PAI-1 mRNA expression is markedly increased by stress, and that the PACAP peptidergic signaling pathway plays a major role in mediating the stress-induced increase in PAI-1 biosynthesis.

Risk prediction in stable angina pectoris

BACKGROUND

Although stable angina pectoris often carries a favourable prognosis, it remains important to identify patients with an increased risk of cardiovascular (CV) complications. Many new markers of disease activity and prognosis have been described. We evaluated whether common and easily accessible markers in everyday care provide sufficient prognostic information.

MATERIALS AND METHODS

The Angina Pectoris Prognosis Study in Stockholm treated 809 patients (248 women) with stable angina pectoris with metoprolol or verapamil double blind during a median follow-up of 3·4 years, with a registry-based extended follow-up after 9·1 years. Clinical and mechanistic variables, including lipids and glucose, renal function, ambulatory and exercise-induced ischaemia, heart rate variability, cardiac and vascular ultrasonography, and psychosocial variables were included in an integrated analysis. Main outcome measures were nonfatal myocardial infarction (MI) and CV death combined.

RESULTS

In all, 139 patients (18 women) suffered a main outcome. Independent predictive variables were (odds ratio [95% confidence intervals]), age (1·04 per year [1·00;1·08], P = 0·041), female sex (0·33 [0·16;0·69], P = 0·001), fasting blood glucose (1.29 per mM [1.14; 1.46], P < 0·001), serum creatinine (1·02 per μM [1·00;1·03], P < 0·001) and leucocyte counts (1·21 per 10(6)  cells/L [1·06;1·40], P = 0·008). Smoking habits, lipids and hypertension or a previous MI provided limited additional information. Impaired fasting glucose was as predictive as manifest diabetes and interacted adversely with serum creatinine. Sexual problems were predictive among men.

CONCLUSIONS

Easily accessible clinical and demographic variables provide a good risk prediction in stable angina pectoris. Impaired glucose tolerance and an elevated serum creatinine are particularly important.

Effects of extracellular DNA on plasminogen activation and fibrinolysis

The increased levels of extracellular DNA found in a number of disorders involving dysregulation of the fibrinolytic system may affect interactions between fibrinolytic enzymes and inhibitors. Double-stranded (ds) DNA and oligonucleotides bind tissue-(tPA) and urokinase (uPA)-type plasminogen activators, plasmin, and plasminogen with submicromolar affinity. The binding of enzymes to DNA was detected by EMSA, steady-state, and stopped-flow fluorimetry. The interaction of dsDNA/oligonucleotides with tPA and uPA includes a fast bimolecular step, followed by two monomolecular steps, likely indicating slow conformational changes in the enzyme. DNA (0.1-5.0 μg/ml), but not RNA, potentiates the activation of Glu- and Lys-plasminogen by tPA and uPA by 480- and 70-fold and 10.7- and 17-fold, respectively, via a template mechanism similar to that known for fibrin. However, unlike fibrin, dsDNA/oligonucleotides moderately affect the reaction between plasmin and α(2)-antiplasmin and accelerate the inactivation of tPA and two chain uPA by plasminogen activator inhibitor-1 (PAI-1), which is potentiated by vitronectin. dsDNA (0.1-1.0 μg/ml) does not affect the rate of fibrinolysis by plasmin but increases by 4-5-fold the rate of fibrinolysis by Glu-plasminogen/plasminogen activator. The presence of α(2)-antiplasmin abolishes the potentiation of fibrinolysis by dsDNA. At higher concentrations (1.0-20 μg/ml), dsDNA competes for plasmin with fibrin and decreases the rate of fibrinolysis. dsDNA/oligonucleotides incorporated into a fibrin film also inhibit fibrinolysis. Thus, extracellular DNA at physiological concentrations may potentiate fibrinolysis by stimulating fibrin-independent plasminogen activation. Conversely, DNA could inhibit fibrinolysis by increasing the susceptibility of fibrinolytic enzymes to serpins.

Weight loss induced by 6-month lifestyle intervention improves early endothelial activation and fibrinolysis in obese adolescents

BACKGROUND

Adolescent obesity is associated with an increased risk of adult obesity and subsequent cardiovascular diseases. The present study aimed to assess the effect of weight loss after 6-month lifestyle intervention in obese adolescents on biomarkers of endothelial activation and fibrinolytic system.

METHODS

Eighty-five obese adolescents aged 10 to 16 years were assigned to a 6-month lifestyle intervention and 61 completed the programme. We examined the effect of the intervention on adhesion molecules (selectin E, soluble intercellular adhesion molecule 1 and soluble vascular adhesion molecule 1) and fibrinolytic parameters [plasminogen activator inhibitor-1 (PAI-1) and fibrinogen]. Thirty-six lean adolescents were studied only at baseline as a comparison group.

RESULTS

Compared with lean participants, obese adolescents at baseline demonstrated significantly higher levels of triglycerides, glucose, insulin, homeostasis model assessment, soluble intercellular adhesion molecule 1, PAI-1 and fibrinogen. After 6-month lifestyle intervention, those obese adolescents with decreased standard deviation score-body mass index (SDS-BMI) displayed significant decreases in insulin (19.2 ± 11.2 vs. 26.8 ± 13.2 mU/L, P≤ 0.01), homeostasis model assessment (4.24 ± 3.19 vs. 6.58 ± 4.08, P≤ 0.01), selectin E (100.2 ± 60.9 vs. 116.0 ± 69.0 ng/mL, P≤ 0.01) and PAI-1 (39.6 ± 38.0 vs. 51.8 ± 25.6 ng/mL, P≤ 0.05) with respect to the baseline levels. No changes in these parameters were observed in the obese adolescents with stable or increased SDS-BMI. The changes of triglycerides after intervention in subgroup with decreased SDS-BMI were significantly greater than those in subgroup with stable SDS-BMI.

CONCLUSIONS

The present study demonstrated increased endothelial activation and impairment of the fibrinolytic system in early life, which is in part reversible by a 6-month lifestyle intervention.

Angiotensin-converting enzyme inhibition and novel cardiovascular risk biomarkers: results from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN) study

BACKGROUND

Beneficial effects of angiotensin-converting enzyme (ACE) inhibitors seem to be mediated by mechanisms that are partly independent of blood pressure lowering. The present study evaluates effects of an ACE inhibitor (ie, fosinopril) intervention on novel cardiovascular risk factors.

METHODS

Data are from the Trial of Angiotensin Converting Enzyme Inhibition and Novel Cardiovascular Risk Factors (TRAIN) study, a double-blind, crossover, randomized, placebo-controlled trial enrolling subjects > or =55 years old with high cardiovascular disease risk profile. Biomarkers of hemostasis (ie, plasminogen activator inhibitor 1, D-dimer), inflammation (ie, C-reactive protein, interleukin-6), and endothelial function (ie, endothelin 1, vascular cell adhesion molecule 1) were measured at the baseline, at the midterm, and at end of follow-up (after 1 year) clinic visits. Paired t test analyses (after Sidak's adjustment, P < .009) were performed to compare biomarkers modifications after fosinopril/placebo interventions.

RESULTS

Mean age of the sample (n = 290, women 43.4%) was 66.0 years old. No significant differences were reported for C-reactive protein, interleukin 6, plasminogen activator inhibitor 1, vascular cell adhesion molecule 1, and endothelin 1 levels in the comparisons between fosinopril and placebo interventions. D-dimer was the only biomarker showing a significant difference between fosinopril intervention (median 0.32 microg/mL, interquartile range 0.22-0.52 microg/mL) and placebo (median 0.29 microg/mL, interquartile range 0.20-0.47 microg/mL, P = .007) when analyses were restricted to participants with higher compliance to treatment and receiving the maximum ACE inhibitor dosage.

CONCLUSIONS

Angiotensin-converting enzyme inhibition does not significantly modify major biomarkers of inflammation, hemostasis, and endothelial function. Further studies should confirm the possible effect of ACE inhibitors on the fibrinolysis pathway.

Low PAI-1 activity in relation to inflammatory parameters, insulin profile and body mass index

BACKGROUND AND OBJECTIVE

High plasminogen activator inhibitor type 1 (PAI-1) activity is associated with inflammatory reactions and insulin resistance, but it is unclear what regulates PAI-1 activity at the low end. The purpose of this study was to investigate if patients with low PAI-1 activity have a lack of inflammatory response or a low insulin level.

DESIGN

Retrospective cohort study with internal controls.

SUBJECTS

Sixty-three patients referred for investigation of bleeding tendency and with low PAI-1 activity were compared with 118 patients with normal or high PAI-1 activity.

OUTCOME

Levels of C-peptide, proinsulin, high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6). Adjustments were made for body mass index (BMI), oral oestrogens and age. Low PAI-1 activity was defined as less than 1 U mL(-1).

RESULTS

Body mass index in the low normal range, oral oestrogens, young age and low C-peptide were significantly associated with low PAI-1 activity and there was a trend for association with IL-6 in univariable analysis. The effect of age disappeared after correction for oral oestrogens and the effect of C-peptide and IL-6 disappeared after further adjustments. Low BMI remained as the strongest predictor of low PAI-1 activity.

CONCLUSION

Patients with bleeding tendency and low PAI-1 activity have inflammatory and insulin profiles similar to those with normal or high PAI-1, whereas BMI seems to be the most important determinant.

Impact of cilazapril on fibrinolytic system in hypertensive patients

Impaired fibrinolysis is associated with thromboembolic complications in hypertensive patients. Cardiovascular morbidity/mortality rates have been reported high even after lowering the elevated blood pressure with antihypertensive drugs. We investigated the effects of clinically used dosages of cilazapril on the fibrinolytic system in hypertensive patients. The present study was performed among 30 hypertensive patients (22 women, eight men), who received 2.5-5.0 mg cilazapril daily for 1 month. Before and after the cilazapril treatment, patients' venous blood was drawn for fibrinolytic tests. The fibrinolytic activity was examined utilizing the euglobulin clot lysis time and fibrin plate methods. Using the fibrin plate method, as compared with the pretreatment group, we observed a 57% increased activity in the hypertensive patients receiving cilazapril (P < 0.001). When assessed by the euglobulin clot lysis time method, the activity due to cilazapril treatment was found to be relatively low, although highly significant (approximately 20%, P < 0.001). Changes in fibrinolytic activity were observed in 23 (77%) hypertensive patients after cilazapril treatment; however, their blood pressure remained normal. The remaining seven patients' (23%) blood pressures and fibrinolytic activity did not change significantly after cilazapril treatment. In conclusion, we suggest that the observed differential fibrinolytic activity between the pre and post cilazapril treatment values is due to the plasminogen activators released from the vascular endothelium, which may have been stimulated by cilazapril. It appears that cilazapril is not only an angiotensin-converting enzyme inhibitor but also a stimulator for fibrinolytic activity, which may be an added component in reducing thromboembolic complications in hypertensive patients.

Fibrinolytic markers and vasodilatory capacity following acute exercise among men of differing training status

We evaluated the effect of differing physical activity patterns on fibrinolysis and vasodilatory capacity using a cross-sectional design with 16 endurance-trained (ET) (mean+/-SE) (28+/-6 years), 14 resistance-trained (RT) (28+/-7 years), and 10 untrained (UT) (26+/-7 years) men. t-PA and PAI-1 activity and t-PA antigen were measured before and after a maximal treadmill test (VO2peak). Vasodilatory capacity was assessed using strain-gauge plethysmography on the forearm following reactive hyperemia (RH) before and after the treadmill test. The ET group had a smaller body mass index (BMI) (22.8+/-0.5 ET, 26.4+/-0.4 RT, 25.1+/-0.8 UT kg m(-2)) (P<0.05) and a greater VO2peak (57+/-1 ET, 42+/-2 RT, 45+/-2 UT mL min(-1) kg(-1)) (P<0.05). Peak vasodilatory capacity (29.7+/-2 ET, 32.0+/-2 RT, 27.4+/-2 UT mL min(-1) 100 mL of tissue) was similar between groups before and after exercise. Area under the curve for forearm blood flow was greater following acute exercise (212 vs. 122, P<0.05), again with no differences between groups. t-PA activity and antigen increased following maximal exercise in all groups (P<0.0001), with no group differences. PAI-1 activity decreased the least in RT after exercise (70% decrease vs. 86% ET and 82% UT; P<0.05). The change in t-PA activity with exercise was not related to exercise-induced change in overall vasodilatory capacity. These findings demonstrate that in healthy young men different physical activity patterns do not appear to impact the exercise-induced changes in fibrinolysis or vasodilatory capacity.

Modulation of serpin reaction through stabilization of transient intermediate by ligands bound to alpha-helix F

Mechanism-based inhibition of proteinases by serpins involves enzyme acylation and fast insertion of the reactive center loop (RCL) into the central beta-sheet of the serpin, resulting in mechanical inactivation of the proteinase. We examined the effects of ligands specific to alpha-helix F (alphaHF) of plasminogen activator inhibitor-1 (PAI-1) on the stoichiometry of inhibition (SI) and limiting rate constant (k(lim)) of RCL insertion for reactions with beta-trypsin, tissue-type plasminogen activator (tPA), and urokinase. The somatomedin B domain of vitronectin (SMBD) did not affect SI for any proteinase or k(lim) for tPA but decreased the k(lim) for beta-trypsin. In contrast to SMBD, monoclonal antibodies MA-55F4C12 and MA-33H1F7, the epitopes of which are located at the opposite side of alphaHF, decreased k(lim) and increased SI for every enzyme. These effects were enhanced in the presence of SMBD. RCL insertion for beta-trypsin and tPA is limited by different subsequent steps of PAI-1 mechanism as follows: enzyme acylation and formation of a loop-displaced acyl complex (LDA), respectively. Stabilization of LDA through the disruption of the exosite interactions between PAI-1 and tPA induced an increase in the k(lim) but did not affect the SI. Thus it is unlikely that LDA contributes significantly to the outcome of the serpin reaction. These results demonstrate that the rate of RCL insertion is not necessarily correlated with SI and indicate that an intermediate, different from LDA, which forms during the late steps of PAI-1 mechanism, and could be stabilized by ligands specific to alphaHF, controls bifurcation between the inhibitory and the substrate pathways.

Dihydropyridine calcium antagonists increase fibrinolytic activity: a systematic review

Calcium antagonists have been shown to be superior over other antihypertensive drugs to prevent stroke. Because this cannot be fully attributed to blood pressure lowering effects, other mechanisms seem to play a role. Previously we found in patients with subarachnoid hemorrhage that nimodipine enhances fibrinolytic activity. The purpose of this systematic review was to investigate the fibrinolytic effect of calcium antagonists in general, especially in patients with hypertension. We systematically studied the entire PUBMED and EMBASE database with the search terms 'calcium antagonist' combined with 'fibrinolysis', '(euglobulin) clot lysis time' (ECLT), 'tissue plasminogen activator' (tPA), or 'plasminogen activator inhibitor' (PAI). Twenty-six prospective studies were identified and 22 manuscripts were included (802 investigated individuals). The results show that calcium antagonists significantly increase fibrinolysis as shown by a reduction of the ECLT standardized mean differences (SMD) -0.58 (95% confidence interval (CI) -1.05 to -0.11)) and an increase of tPA activity (SMD 0.73 (95% CI 0.25 to 1.21)). This increase of fibrinolysis is apparently caused by an increase of the tPA antigen level (SMD 0.16 (95% CI -0.05 to 0.37)) and a decrease of the plasminogen activator inhibitor-1 antigen antigen (SMD -0.36 (95% CI -0.74 to 0.02)). A sensitivity analysis showed that dihydropyridines, but not phenylalkylamines, exert a fibrinolytic effect. This fibrinolytic effect is not only seen in patients with subarachnoid hemorrhage but also in hypertensive patients. In conclusions, calcium antagonists increase fibrinolytic activity. This may add to the beneficial pharmacological effect of calcium antagonists to prevent ischemic events in patients with hypertension and subarachnoid hemorrhage.

Myocardial infarction with normal coronary arteries: a conundrum with multiple aetiologies and variable prognosis: an update

The existence of myocardial infarction despite angiographically normal coronary arteries was recognized more than 30 years ago. Since then, various series of such patients have been described, but the aetiology and pathogenesis of the condition are still a source of debate. Evidence exists for a role of coronary vasospasm, thrombosis, embolization and inflammation, per se or combined, in determining the occurrence of myocardial infarction in the presence of angiographically normal coronary arteries. Endothelial dysfunction, possibly superimposed to nonangiographically evident atherosclerosis, may be an underlying common feature predisposing to the acute event. Additionally, myocarditis may explain some of these occurrences. Myocardial infarction with normal coronary arteries is therefore likely the result of multiple pathogenetic mechanisms. Although most reports emphasize the good prognosis of this condition, in general much better than myocardial infarction with coronary artery disease, prognosis is likely variable according to the underlying mechanism. This review summarizes current knowledge on this condition and examines areas of recent progress.

Impact of weight reduction on production of platelet-derived microparticles and fibrinolytic parameters in obesity

INTRODUCTION

Generation of platelet-derived microparticle (PMP) is implicated in cardiovascular disease (CVD). However, the influence of adiposity and weight reduction on PMP generation remains to be fully elucidated. We compared PMP generation and fibrinolytic parameters between 49 non-diabetic obese (obese group) and 37 age-matched non-obese subjects (control group), and compared the effects of weight reduction on the parameters between a 12-week calorie restricted diet and diet with aerobic exercise in obese subjects.

MATERIALS AND METHODS

PMP, plasma levels of plasminogen activator inhibitor-1 (PAI-1) activity and tissue-type plasminogen activator (t-PA) antigen were measured before and after intervention.

RESULTS

Before intervention, PMP, PAI-1 activity and t-PA antigen values were elevated in the obese group compared with the control group. In all 86 subjects of both groups, these three parameters correlated with body mass index, waist circumference and fat tissue mass. There was a positive correlation between plasma levels of fibrinolytic parameters and visceral fat area (VFA). PMP values correlated with subcutaneous fat area (SFA). The intervention significantly reduced PMP, PAI-1 activity and t-PA antigen levels. There was a significant correlation between percentages of changes in PMP values and those in BMI, fat tissue mass and VFA in the obese group. No additional effect of exercise on PMP or fibrinolytic parameters was observed.

CONCLUSIONS

Overproduction of PMP and fibrinolytic abnormalities may be associated with excessive adipose tissue. Weight reduction by either calorie restriction with or without exercise improves fibrinolytic abnormalities and PMP overproduction, probably through reduction of adipose tissue.

Tissue plasminogen activator on admission is an important predictor of 30-day mortality in patients with acute myocardial infarction undergoing primary angioplasty

Tissue plasminogen activator (tPA) is emerging as an important risk factor for coronary heart disease, but the association between tPA concentration and mortality in acute myocardial infarction (AMI) remains uncertain. We studied the relationship between tPA antigen level on admission and 30-day mortality in 226 consecutive patients with AMI undergoing primary angioplasty. Death within 30 days occurred in 13 patients (5.7%). The concentration of tPA was significantly higher among the 13 patients who died than among the 213 who survived (26.5+/-16.3 versus 12.5+/-8.5 ng/mL, p<0.001). Compared with those in the lowest quartile (<9 ng/mL), patients in the highest quartile (>16 ng/mL) had a relative risk of subsequent death of 13.1 (p=0.014). In a Cox regression model, a tPA concentration >19 ng/mL was independently associated with mortality (HR 12.1, 95% CI, 1.9-76.7, p=0.001). This cutoff value had a 76.9% sensitivity and an 85.9% specificity for predicting 30-day mortality. tPA concentration was also higher in patients with severe heart failure (20.9+/-14.2 ng/mL versus 11.7+/-7.5 ng/mL, p=0.001) or ventricular tachyarrhythmia (24.3+/-13.9 ng/mL versus 12.2+/-8.4 ng/mL, p=0.001). In conclusions, elevated tPA antigen at initial presentation in patients with AMI was associated with higher short-term risk of death, suggesting that tPA may be a useful prognostic biomarker for the early risk stratification of these patients.

Elevated platelet P-selectin expression and platelet activation in high risk patients with uncontrolled severe hypertension

BACKGROUND

Uncontrolled severe hypertension is associated with alarming rates of cardiovascular events but the mechanisms of vascular injury are not well understood. Recent investigative interest has focused on platelet activation and platelet P-selectin (CD62P) as direct mediators of vascular inflammation and injury. We investigated the association of extreme blood pressure (BP) elevation with platelet P-selectin and fibrinolytic markers in high risk patients with severe hypertension.

METHODS

Cross-sectional comparison of platelet CD62, tissue plasminogen activator antigen (tPA), and plasminogen activator inhibitor-1 activity (PAI-1) among 3 BP groups: untreated severely hypertensive patients (SHT; n=18), untreated mildly hypertensive patients (MHT; n=19), and normotensive controls (NT; n=16).

RESULTS

Platelet CD62 was greatest in SHT (p=0.00008) and showed a strong correlation with both systolic (p=0.0002, r=0.52) and diastolic (p=0.0003, r=0.52) BP. tPA was greater in SHT than MHT or NT (ANOVA; p=0.02) and correlated with diastolic BP but not SBP. PAI-1 did not correlate with either SBP or DBP but was related to body mass index, diabetes, and dyslipidemia.

CONCLUSIONS

Platelet CD62 demonstrated a strong and graded association with both systolic and diastolic BP that persisted in the presence of multiple concomitant risk factors. The association of BP with CD62P was stronger than with either PAI-1 or tPA-Ag. Platelet activation and platelet CD62 increase in a BP-dependent manner and this relationship persists at extreme levels of BP. Platelet activation and platelet CD62 may participate in the accelerated target organ injury observed in high risk patients with severe hypertension.

Cardiac fibrinolytic capacity is markedly increased after brief periods of local myocardial ischemia, but declines following successive periods in anesthetized pigs

BACKGROUND

Fibrinolysis in blood is mainly reflected by the activities of tissue plasminogen activator (tPA) and of plasminogen activator inhibitor-1 (PAI-1). The effect of myocardial ischemia on their activities in the coronary circulation is, however, not established.

OBJECTIVES

With an improved experimental model, we therefore examined the effect of a brief period of myocardial ischemia on their activities. Furthermore, the consequences of repeated periods of ischemia, mimicking the situations in patients with unstable angina, were investigated.

METHODS

In six anesthetized pigs, we occluded the distal left anterior descending coronary artery (LAD) four times for 10 min with 40 min intervals and determined the activities of tPA and PAI-1 in arterial and coronary venous blood. By simultaneously recording LAD flow, we could estimate cardiac release of these factors at baseline conditions and during reperfusion.

RESULTS

Neither net cardiac release of PAI-1 nor alterations in plasma PAI-1 levels were demonstrated during the experiment. However, a significant net release of tPA activity of 10.4 +/- 3.2 IU mL(-1) (P < 0.005) was recorded during baseline conditions. During reperfusion following the first period of ischemia, the cardiac release of tPA activity increased to a peak of 103 +/- 30-fold baseline release, but declined progressively after repeated periods of ischemia. After the fourth period, tPA release did not exceed an estimated baseline accumulation during ischemia and early reperfusion.

CONCLUSIONS

In this porcine model, a substantial local increase in fibrinolytic capacity was observed after brief periods of ischemia, but declined subsequently by repeated periods of ischemia.

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.

Favourable long term prognosis in stable angina pectoris: an extended follow up of the angina prognosis study in Stockholm (APSIS)

OBJECTIVE

To evaluate the long term prognosis of patients with stable angina pectoris.

DESIGN

Registry based follow up (median 9.1 years) of patients participating in the APSIS (angina prognosis study in Stockholm), which was a double blind, single centre trial of antianginal drug treatment.

PATIENTS

809 patients (31% women) with stable angina pectoris < 70 (mean (SD) 59 (7) years at inclusion) and an age and sex matched reference population from the same catchment area.

INTERVENTIONS

Double blind treatment with metoprolol or verapamil during 3.4 years (median), followed by referral for usual care with open treatment.

MAIN OUTCOME MEASURES

Cardiovascular (CV) death and non-fatal myocardial infarction (MI) in the APSIS cohort and total mortality in comparison with reference subjects.

RESULTS

123 patients died (41 MI, 36 other CV causes) and 72 had non-fatal MI. Mortality (19% v 6%, p < 0.001) and fatal MI (6.6% v 1.6%, p < 0.001) were increased among male compared with female patients. Diabetes, previous MI, hypertension, and male sex independently predicted CV mortality (p < 0.001). Diabetes greatly increased the risk in a small subgroup of female patients. Male patients had higher mortality than men in the reference population during the first three years (cumulative absolute difference 3.8%) but apparently not thereafter. Female patients had similar mortality to women in the reference population throughout the 9.1 years of observation.

CONCLUSIONS

Female patients with stable angina had similar mortality to matched female reference subjects but male patients had an increased risk. Diabetes, previous MI, hypertension, and male sex were strong risk factors for CV death or MI.

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 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.

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.

The complex between tPA and PAI-1: risk factor for myocardial infarction as studied in the SHEEP project

INTRODUCTION

The tPA/PAI-1 complex seems to be an important biochemical marker for myocardial reinfarction. Therefore we explored the distribution, correlation and interaction of plasma concentrations of tPA/PAI-1 complex in all available patients and matched controls in the Stockholm Heart Epidemiology Program (SHEEP).

METHODS AND PATIENTS

The SHEEP study is a case control study of 2246 patients with a first myocardial infarction (MI), of which 1267 surviving patients were subjected to blood sampling about 3 months after MI and compared with a control group, matched for age, sex and living area within the Stockholm County. The study consists of 886 (591 men and 295 women) patients and 1198 (753 men and 445 women) matched controls, who were all analysed for plasma tPA/PAI-1 complex.

RESULTS

The plasma concentration of tPA/PAI-1 complex was significantly associated with the risk for MI, for both genders. Synergistic interactions were observed in men for the co exposure to high plasma tPA/PAI-1 complex concentrations in combination with smoking (OR=4.6) or diabetes mellitus (OR=7.9). Synergism was also seen in combination with exposure to serum hypercholesterolemia or increased levels of apolipoprotein B. An antagonistic effect of the co exposure to high tPA/PAI-1 complex and hypertension was found among men with a similar tendency among women, but an antagonistic effect of increased waist/hip ratio was only observed among the women.

CONCLUSIONS

Measuring the plasma concentration of tPA/PAI-1 complex might be of practical value in assessing risk of MI for both genders, especially in those who are smokers or in patients with manifest diabetes mellitus.

Atherosclerosis as Inflammation

Atherosclerosis has traditionally been attributed to disordered cholesterol metabolism with associated accumulation of lipid substrate in the arterial wall. It is now believed that systemic and local inflammatory events mediate all phases of plaque development, progression, and degeneration. No longer regarded as a bland, mechanical process, plaque evolution is now best understood as a pitched battle between proinflammatory and anti-inflammatory cellular and molecular elements. Not unlike models of chronic wound healing or ischemia-reperfusion, the biologic state of a plaque at any given time is transient and mutable, reflecting a dynamic balance of numerous local and circulating inflammatory forces. Dreaded complications of the disease such as myocardial infarction and stroke result from acute shifts in this balance in favor of plaque instability and vulnerability over stable states of chronic inflammation. The purpose of this article is (1) to review the inflammatory pathogenesis of atherosclerosis on a molecular basis, (2) describe several of the emerging inflammatory biomarkers currently being investigated with particular interest in their possible roles as direct mediators of vascular disease, and (3) identify several important implications for diagnosis and therapy.

Allelic frequency of the PAI-1 4G/5G promoter polymorphism in patients with type 2 diabetes mellitus and lack of association with PAI-1 plasma levels

Plasminogen activator inhibitor-1 (PAI-1) levels were found to be associated with obesity, indicating that adipocytes might influence PAI-1 plasma levels. In addition, the 4G/5G promoter polymorphism of the PAI-1 gene possibly modulates PAI-1 gene transcription and, as a consequence, PAI-1 plasma levels. Metabolic parameters, diabetes complications, PAI-1 plasma levels, and PAI-1 promoter genotypes were determined and were tested for correlation in 547 Caucasian patients with type 2 diabetes. Genotyping was performed by using allele-specific PCR, and PAI-1 plasma levels were measured in 547 well-characterized subjects with type 2 diabetes. The allelic frequencies of the polymorphism (0.56 for the 4G-genotype, 0.44 for the 5G-genotype) were not different from those observed in nondiabetic controls. The PAI-1 concentration was positively associated with MI, but not with the 4G/5G polymorphism. Statistical analysis of metabolic parameters, diabetic complications, and the 4G/5G polymorphism revealed that serum fibrinogen levels were significantly higher in the 4G/4G subgroup compared with the 4G/5G and 5G/5G subgroups. The correlation between serum fibrinogen and 4G allele remained significant, even when additional variables, such as gender, age, BMI, duration of diabetes, and HbA1c, were controlled. In patients with type 2 diabetes mellitus, the PAI-1 4G/5G promoter polymorphism does not predict PAI-1 plasma levels and is not associated with common metabolic parameters besides fibrinogen levels.

The plasma levels of plasminogen activator inhibitor-1 in subjects with white coat hypertension

High plasminogen activator inhibitor-1 (PAI-1) levels are potential risk factors for cardiovascular disease. The risk profile of white coat hypertension (WCHT) has not yet been completely clear. In this study, we aimed to determine the plasma levels of PAI-1, markers of fibrinolysis and increased cardiovascular disease risk, in a group with WCHT and to obtain clinical results by comparing WCHT group with hypertensive and healthy groups. Age and sex matched 30 patients with WCHT, 30 patients with sustained hypertension, and 30 healthy subjects were included in the study. The plasma levels of PAI-1 were significantly higher in sustained hypertension group than in WCHT group (p < 0.01). There were significantly higher levels in patients with WCHT than in control group (p < 0.01). Our data suggests one possible mechanism by which WCHT subjects may be at increased cardiovascular risk.

4G/5G polymorphism of the plasminogen activator inhibitor-1 gene and risk of restenosis after coronary artery stenting

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) has been proposed as a candidate risk factor for restenosis after coronary artery stenting. Transcription, level, and activity of PAI-1 are influenced by the 4G/5G polymorphism in the promoter region of PAI-1 gene. The polymorphism may therefore affect wound-healing processes in injured blood vessels and influence restenosis.

METHODS

In 1850 consecutive patients, angiographic measures of restenosis and the clinical outcome at 30 days and 1 year after stent implantation were evaluated. Angiographic restenosis was defined as > or =50% diameter stenosis determined at follow-up angiography, performed 6 months after stenting. The 4G/5G genotypes were determined with TaqMan technique.

RESULTS

Among the patients, the frequency of the 4G allele was 0.55. Follow-up angiography was done in 84% of the patients. We observed restenosis in 32.5% of 4G/4G carriers, 32.2% of 4G/5G carriers, and 35.7% of 5G/5G carriers (P =.52). The occurrence of a major adverse event (death, myocardial infarction, or target vessel revascularization due to restenosis-induced ischemia) was 5.6% in 4G/4G carriers, 5.3% in 4G/5G carriers, and 4.6% in 5G/5G carriers at 30 days (P =.80), and 24.7% in 4G/4G carriers, 23.0% in 4G/5G carriers, and 26.2% in 5G/5G carriers at 1 year (P =.45).

CONCLUSION

The 4G/5G polymorphism of the PAI-1 gene is not associated with an increased risk of thrombotic and restenotic events after coronary artery stenting.

Neointima formation and thrombosis after vascular injury in transgenic mice overexpressing plasminogen activator inhibitor-1 (PAI-1)

The controversial role of plasminogen activator inhibitor-1 (PAI-1) in neointima formation and restenosis was studied with the use of a vascular injury model in transgenic mice overexpressing murine PAI-1 (PAI-1 Tg) and in wild-type (WT) controls. Despite the high circulating PAI-1 levels in the PAI-1 Tg mice (52 +/- 9.8 ng mL-1 vs. 0.76 +/- 0.17 ng mL-1 in WT mice), no significant fibrin deposition was observed in non-injured femoral arteries of 8- to 12-week-old mice. Two weeks after severe electric injury, extensive and comparable fibrin deposition was observed in both genotypes, despite a significantly reduced in situ fibrinolytic activity in arterial sections of the PAI-1 Tg mice. The neointimal and medial areas were similar in WT and PAI-1 Tg mice, resulting in comparable intima/media ratios (e.g. 0.94 +/- 0.25 and 1.04 +/- 0.17 at the center of the injury). Nuclear cell counts in cross-sectional areas of the neointima of the injured region were also comparable in arteries from WT and PAI-1 Tg mice (224 +/- 63, 233 +/- 20), and the distribution pattern of alpha-actin-positive smooth muscle cells was similar. These findings indicate that in a vascular injury model that induces extensive and persistent fibrin deposition in femoral arteries of mice, overexpression of PAI-1 does not affect neointima formation.

Effect of plasminogen activator inhibitor-1 in diabetes mellitus and cardiovascular disease

Concentrations of plasminogen activator inhibitor-1 (PAI-1) are elevated beginning at the stage of impaired glucose tolerance and continuing through the development of diabetes mellitus and the metabolic syndrome. Evolving evidence of the central role of PAI-1 in mediating fibrosis and thrombosis increasingly supports the theory that it is a significant risk factor for macrovascular complications and cardiovascular disease, particularly in patients with diabetes. Several clinical studies have demonstrated a strong correlation between circulating PAI-1 levels and cardiovascular events and mortality. With the potentially severe effects of elevated PAI-1 levels becoming evident, there is increased interest in developing therapies targeted at reducing PAI-1 expression or circulating concentrations. Thus far, weight loss, inhibitors of the renin-angiotensin system, and insulin sensitization through use of thiazolidinediones (TZDs) appear to be the most promising strategies for managing elevated PAI-1 levels. Of these, TZD therapy is the only one that provides the benefits of both long-term glycemic control and improved cardiovascular risk profile. This article reviews the regulation of PAI-1, its activity in various disease states, and available treatment options.

The expanding scope of the metabolic syndrome and implications for the management of cardiovascular risk in type 2 diabetes with particular focus on the emerging role of the thiazolidinediones

Over the last decade, new factors including endothelial dysfunction, vascular inflammation, and abnormalities of blood coagulation have joined more established components of the metabolic syndrome, such as hyperglycemia, hypertension, dyslipidemia, and visceral obesity. Many of these factors are known to promote atherosclerosis and the clustering of metabolic abnormalities within the syndrome makes a major contribution to the increased risk of cardiovascular disease and death associated with type 2 diabetes. Given that most patients have multiple cardiovascular risk factors, good glycemic control does not, by itself, adequately reduce the burden of cardiovascular disease associated with diabetes and clinical management needs to address the full profile of cardiovascular risk. The thiazolidinediones have potentially beneficial effects on many components of the metabolic syndrome and so may help to improve cardiovascular outcomes in type 2 diabetes.

Plasminogen activator inhibitor contributes to the coronary wall thickening in patients with angiographically normal coronary

INTRODUCTION

Angiographically normal coronary arteries have concealed intimal thickening that importantly contribute to coronary arterial disease activity. Increased plasma levels of plasminogen activator inhibitor (PAI) are associated with myocardial infarction and atherosclerosis. However, it remains unclear whether the PAI contributes to vascular wall thickening detected by intravascular ultrasound (IVUS) in normal coronary angiogram. The aim of this study was to evaluate if the PAI activity contributes to the extent of atherosclerotic changes in angiographically normal coronary arteries using IVUS technique.

MATERIALS AND METHODS

We studied 33 consecutive patients with normal coronary angiograms. These patients were divided into a high level of plasma PAI activity group (H-PAI; n=12) and a normal range of PAI activity group (N-PAI; n=21), according to the plasma PAI activity levels.

RESULTS

The average of "percent intima+media area (%I+M area)" and "maximal intima+media (I+M) thickness" were significantly greater in the H-PAI group as compared with those in the N-PAI group (p<0.05). Minimal lumen diameter and lumen area were comparable between these groups. The plasma PAI activity level was the independent predictor of increase in maximal I+M thickness, in multiple regression analysis with the traditional risk factors as covariates.

CONCLUSIONS

Thickened intima+media of angiographically normal coronary arteries were associated with high plasma level of PAI activity, independently of other traditional risk factors. PAI may contribute to the pathogenesis of coronary intimal thickening that might increase coronary arterial tone.

Managing the hypertensive patient with ischemic heart disease

Thiazide diuretics, b-blockers, calcium channel blockers, and angiotensin converting enzyme (ACE) inhibitors are all superior to placebo for the primary prevention of coronary events in patients with hypertension. Recent studies have shown that ACE inhibitors are better than other antihypertensive agents in lowering overall cardiovascular morbidity and mortality, especially stroke. Blood pressure should be aggressively lowered (to < 140/90 mm Hg), especially in diabetic patients (to < 130/80 mm Hg), but care should be exercised in lowering the diastolic blood pressure below 65 mm Hg in patients with significant occlusive coronary artery disease. Hypertension in patients with stable angina should be treated with a b-blocker (alternatively a calcium channel blocker) together with an ACE inhibitor. Patients with hypertension and acute coronary syndrome (unstable angina or myocardial infarction) should be treated with a b-blocker, and with an ACE inhibitor if there is left ventricular dysfunction. A thiazide diuretic and/or a dihydropyridine calcium channel blocker could be added for blood pressure control. Calcium channel blockers should be avoided if there is significant left ventricular dysfunction.

Plasma concentrations of fibrinolytic factors in the subacute phase of myocardial infarction predict recurrent myocardial infarction or sudden cardiac death

BACKGROUND

The prognostic value of plasma concentrations of tissue type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), and C-reactive protein has been reported in patients with coronary artery disease. However, the association between cardiac events and these factors during the acute and subacute phases of myocardial infarction (MI) is unknown. The purpose of this study was to determine whether elevated plasma concentrations of t-PA, PAI-1, and C-reactive protein in patients with MI are associated with future recurrent MI or sudden cardiac death.

METHODS

We studied 106 consecutive patients who survived a confirmed first MI between 1993 and 1998 in our hospital. The control group consisted of 50 patients who had no significant coronary artery stenosis. Blood samples were obtained at the time of admission for acute MI and on the 28th day after admission. Patients were followed for a mean of 50 months after these measurements. The primary end points were sudden cardiac death and fatal or nonfatal acute MI.

RESULTS

Of the 92 patients who were available for follow-up, 10 had cardiac events. Both the plasma t-PA and PAI-1 concentrations were elevated on day 1 of acute MI compared to the control group and decreased by day 28, but remained higher than those in the controls. Plasma C-reactive protein concentration was also elevated on day 1 and decreased by day 28. Using a stepwise variable choice model of Cox proportional hazards analysis including these fibrinolytic factors and C-reactive protein, only the t-PA concentration in the subacute phase was a significant predictor of cardiac events (relative risk per S.D. 3.20, P<0.01). We further found that independent of other risk factors, an elevated t-PA concentration was predictive of cardiac events.

CONCLUSIONS

This study reveals that a rise in endogenous t-PA concentration during the subacute phase of MI could predict recurrent MI or sudden cardiac death.

Hypofibrinolytic state in HIV-1-infected patients treated with protease inhibitor-containing highly active antiretroviral therapy

Decreased insulin sensitivity, hyperlipidemia, and body fat changes are considered as risk factors for coronary heart disease (CHD). A clustering of such factors (metabolic syndrome [MSDR]) exponentially increases the risk. Impaired fibrinolysis and increased coagulation are additional independent risk factors for CHD. We studied the effects of protease inhibitor (PI)-containing highly active antiretroviral therapy (HAART) on metabolic and hemostatic parameters in 363 HIV-infected individuals, of whom 266 were receiving PI-containing HAART and 97 were treatment naive. The fasting plasma levels of insulin, glucose, triglycerides, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, plasminogen activator inhibitor type 1 (PAI-1), and fibrinogen were evaluated together with the areas of visceral adipose tissue and the visceral adipose tissue/subcutaneous adipose tissue area ratio. The levels of insulin, triglycerides, cholesterol, and low-density lipoprotein cholesterol; visceral adipose tissue area; low-density lipoprotein/high-density lipoprotein ratio; and visceral adipose tissue/subcutaneous adipose tissue area ratio were significantly increased in patients receiving PI-containing HAART compared with treatment-naive patients. The levels of PAI-1 and fibrinogen were significantly higher in patients receiving PI-containing HAART. PAI-1 levels were higher in individuals with MSDR but also in patients without MSDR who were receiving PI-containing HAART. PAI-1 was independently correlated to use of PI-containing HAART, triglyceride level, insulin level, and body mass index (p <.001). These findings suggest that patients receiving PI-containing HAART have decreased fibrinolysis and increased coagulability, which may thus represent additional risk factors for cardiovascular disease in this patient group.

The mechanisms of thrombotic risk induced by hormone replacement therapy

OBJECTIVES

To review the available information on the action of hormones on the mechanisms involved in thrombotic risk.

RESULTS AND CONCLUSIONS

Thrombosis plays a crucial role in the genesis and progression of both coronary heart disease (CHD) and venous thromboembolic disease (VTED), the two main forms of cardiovascular disease. Two main determinants of the thromboembolic phenotype, hypercoagulable state and altered endothelium, accumulate much of the work performed on the influence of hormones on thrombosis. Information has accumulated mainly for oestrogens, but increasing evidences support a role for progestogens. The sensitivity of each of the three components of the hemostatic balance, the coagulation cascade, the anticoagulant system and fibrinolysis, to oestrogens has been widely examined in the literature. Functional tests suggest that HRT is accompanied by a procoagulant state. Much of the work has concentrated on changes induced on reputable indicators of risk for either CHD or VTED. Distinct indicators of increased coagulability, such as resistance to activated C protein, antithrombin or tissue factor pathway inhibitor have been selected for VTED, whereas factor VII, fibrinogen, and defective fibrinolysis, for CHD. Different states of genetic susceptibility have been involved in both forms of the disease. The status of health of endothelium, defines another scenario for attention in CHD. A long-term anti-atherogenic action of oestrogens, which may be associated with short-term risk in cases of atherosclerosis-induced endothelial dysfunction, may most adequately explain much of the clinical observation. In both CHD and VTED, the procoagulant changes initiate soon after HRT administration.

Remnant lipoproteins induce endothelial plasminogen activator inhibitor-1

Remnant lipoproteins (RLPs) accumulate in type III hyperlipoproteinemia, a condition associated with significant cardiovascular morbidity. The effect of RLPs on fibrinolysis is unknown. Our aim was to study the effect of RLPs on endothelial expression of plasminogen activator inhibitor-1 (PAI-1). After 24-h culture of human aortic endothelial cells with RLPs at concentrations of 0 (control), 0.038, or 0.076 mg triglyceride/mL, postculture PAI-1 antigen concentrations were: 870 +/- 80, 1963 +/- 183 (P = 0.005), and 3551 +/- 177 ng/mL (P < 0.001), respectively. Furthermore, after 24-h incubation of endothelial cells with RLPs (0 or 0.076 mg triglyceride/mL), PAI-1 activity increased from 0.667 +/- 0.144 to 1.268 +/- 0.198 U/mL, respectively (P = 0.008) and endothelial PAI-1 mRNA increased to 2.7 +/- 0.66 that of control (P = 0.048). In conclusion, RLPs from patients with type III hyperlipoproteinemia induce endothelial cell PAI-1 expression, which may contribute to a prothrombotic state.

Myocardial injury and systemic fibrinolysis in patients undergoing repair of ruptured abdominal aortic aneurysm: a preliminary report

BACKGROUND

ruptured abdominal aortic aneurysm (AAA) is associated with inhibition of systemic fibrinolysis. Hypofibrinolysis is a risk factor for ischaemic myocardial injury, one of the commonest complications of ruptured AAA repair. Cardiac troponin I (cTnI) is one of the most sensitive and specific marker of myocardial injury currently available.

OBJECTIVE

To examine, for the first time, the relationship between fibrinolytic activity and myocardial injury in patients operated for ruptured AAA.

METHODS

Twenty patients (18 men and 2 women of median age 74, range 65-86 years) undergoing repair of ruptured AAA were prospectively studied. Plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) activity were measured pre-operatively, immediately before and five minutes following aortic clamp release. Serum cTnI was measured pre-operatively, 6 and 24 h following clamp release. Results cTnI was detectable at one or more sample points in 13 (65%) patients, and in 7 out of 8 patients who suffered major cardiac complications. There was a significant negative correlation between pre-operative t-PA activity and cTnI before operation (r =-0.55, p = 0.01) and 6 h ( r =-0.51, p =0.02) after clamp release. There was a significant positive correlation between pre-operative PAI activity and cTnI before operation (r =+0.50, p =0.03), 6 h ( r =+0.47, p =0.04) and 24 h ( r =+0.50, p =0.03) after clamp release. There was no correlation between pre- and intra-operative hypotension or blood transfusion requirement and cTnI release.

CONCLUSIONS

Hypofibrinolysis during ruptured AAA repair is associated with the development of peri-operative myocardial injury. The causal mechanisms underlying this state are not clear but treatment of this prothrombotic/hypofibrinolytic diathesis may help to limit myocardial cell necrosis.

Both atenolol and propranolol blunt the fibrinolytic response to exercise but not resting fibrinolytic potential

This randomized, double-blind trial found that tissue plasminogen activator activity increased and plasminogen activator inhibitor-1 activity decreased significantly more with exercise during placebo treatment than during treatment with beta blockade. These results suggest that beta blockade blunts the fibrinolytic response to maximal exercise.

Short- and long-term risk factors for sudden death in patients with stable angina

Sudden death is most common and often the first manifestation of coronary heart disease although its risk is difficult to predict. It has been studied mainly in patients with severe ventricular arrhythmia or recent myocardial infarction, but little is known about the different risk factors for short- and long-term risk of sudden death in patients with stable angina. To assess risk factors for sudden death in patients with stable angina and angiographically proven coronary artery disease, 319 consecutive patients were recruited prospectively and followed-up. Patients with clinical heart failure or recent myocardial infarction were excluded. Clinical, angiographic and biological variables were recorded. The association between each variable and the risk of sudden death was assessed in univariate and logistic multivariate analysis. There were 25 sudden deaths during the follow-up period (97+/-29 months). The univariate predictors in the short-term (2 years) were: peripheral arterial disease, left ventricular hypertrophy, low density lipoprotein cholesterol and ejection fraction. The independent predictors were: peripheral arterial disease (relative risk: 6.3), ejection fraction (relative risk 1.05) and low density lipoprotein (relative risk: 1.8). In the long-term (8-10 years), body mass index, coronary score, ejection fraction and fibrinogen were univariate predictors. Only body mass index (relative risk: 1. 2), ejection fraction (relative risk: 1.06) and fibrinogen (relative risk: 2) remained independent predictors. The risk factors for sudden death in stable angina were time-dependent, peripheral arterial disease appeared as the best predictor with LDL for short time, and body mass index (obesity: index >27) and fibrinogen for long time. Ejection fraction was the only time-independent predictor.