The 4G/5G polymorphism of the plasminogen activator inhibitor gene is associated with the time course of progression to acute coronary syndromes

Plasminogen Activator Inhibitor-1 Polymorphisms and Risk of Coronary Artery Disease: Evidence From Meta-Analysis and Trial Sequential Analysis

A systematic review and meta-analysis were conducted to find out if there was association between Plasminogen Activator Inhibitor-1 (PAI-1) gene polymorphisms (- 844 G > A and - 675 4G > 5G) and susceptibility to coronary artery disease (CAD). Search of electronic databases was performed and the pooled odds ratio (OR) and 95% confidence interval (CI) were exerted to evaluate the pooled association between the single-nucleotide polymorphisms (SNPs) and risk of CAD. For - 675 4G > 5G SNP, dominant (OR = 0.90), recessive (OR = 0.90), allelic (OR = 0.91), homozygous (OR = 0.84), and heterozygous (OR = 0.96) models were significantly associated with decreased risk of CAD. Moreover, all five genetic models were associated significantly with decreased CAD risk in the Causation and Arab populations. The results in Asians were marginally significant in recessive, allelic, and homozygote models. The male gender was found to be a risk factor in individuals with PAI-1 4G > 5G SNP in the dominant model (OR = 0.89), recessive model (OR = 0.91), allelic model (OR = 0.92), homozygous model (OR = 0.86), and heterozygous model (OR = 0.91). The results of pooled ORs for overall populations and subgroup analysis by ethnicity reject any association between PAI-1 gene - 844 G > A polymorphism and CAD risk under all genetic comparisons. The results of this meta-analysis indicated that PAI-1 4G > 5G SNP was associated with decreased risk of CAD in the overall population as well as in the Asians, Caucasians, and Arab populations. However, the PAI-1 gene - 844 G > A polymorphism had no significant association with susceptibility to CAD.

Genotype Variations and Association between PAI-1 Promoter Region (4G/5G and -844G/A) and Susceptibility to Acute Myocardial Infarction and Chronic Stable Angina

The present study aimed at investigating the 4G/5G and -844G/A polymorphisms and plasma concentration of PAI-1 in patients with acute myocardial infarction (AMI) and chronic stable angina (CSA) in Indian population. It included 100 patients with AMI and stable angina and 100 healthy controls. All study subjects were typed for two PAI polymorphisms (4G/5G and -844G/A) through PCR-RFLP and level of PAI through ELISA. The comparison of AMI and CSA independently with control in terms of PAI-1 level was statistically significant but not between AMI and CSA. The frequency of 4G/4G and 4G/5G genotype and 4G allele was significantly higher in AMI cases than in control and was found to increase the risk of AMI. There was a significant relationship between 4G/5G polymorphism and AMI risk under the dominant and codominant genotype. The frequency of 4G/4G genotype and 4G allele was significantly higher in CSA cases than in control group and increases the risk of CSA. There was no significant association between 4G/5G polymorphism and CSA risk under recessive, dominant, and codominant models. The genotype and allelic frequencies difference between the cases (AMI and CSA) and control with regard to -844G/A polymorphisms were statistically nonsignificant. Also, we did not detect any significant association of -844G/A polymorphism with AMI and CSA in recessive, dominant, and codominant models. Along with the traditional risk factors, the 4G/5G allele polymorphism is an independent risk factor for the development of AMI. The detection of 4G/5G allele may therefore be helpful in primary prevention. Patients who carry the 4G/5G allele polymorphism have high concentrations of PAI-1, which might be involved in incidents leading to AMI. The present study for the first time revealed significant association of 4G/5G allele polymorphism with high risk of AMI in Indian population and will be helpful in identifying the genetic risk factors associated with AMI and CSA and for better management of diagnostic measures.

Plasminogen activator inhibitor-1 polymorphisms as a risk factor for chronic periodontitis in North Indian population

Objectives

Impaired plasminogen activator inhibitor-1 (PAI-1), controlling coagulation and the fibrinolytic system is supposed to be involved in the pathogenesis of periodontitis. This study was performed to examine the association of PAI-1 gene polymorphisms with Chronic Periodontitis (CP) and alveolar bone loss severity involved with the disease and for understanding the role of genetic contributions in disease progression.

Methods

87 volunteers were included in the study. Genomic DNA was isolated from peripheral blood, subsequently, DNA samples were subjected to polymerase chain reaction and endonuclease digestion. Direct gene sequencing were performed for all the samples to identify genotype polymorphisms (rs 11560324) in the 3' untranslated region of PAI-1 gene. For bone loss assessment full mouth IOPA was taken.

Results

Statistical analysis showed that for SNP PAI-I in 3' UTR, genotype CC (homozygous mutant) and allele C (mutant) has a risk associated with CP, although statistically significant association was not found. An increased risk of association of disease severity with CG (heterozygous mutant) and CC (homozygous mutant) genotypes, i.e., an increased carriage rate of genotype CG and CC (homozygous mutant) was evident with the increase in the severity of CP, highlighting an increased susceptibility to CP due to this gene polymorphisms.

Conclusion

PAI-1 genotype has a risk association with CP and alveolar bone loss severity in North-Indian population.

Genetics of Plasminogen Activator Inhibitor-1 (PAI-1) in a Ghanaian Population

Plasminogen activator inhibitor 1 (PAI-1), a major modulator of the fibrinolytic system, is an important factor in cardiovascular disease (CVD) susceptibility and severity. PAI-1 is highly heritable, but the few genes associated with it explain only a small portion of its variation. Studies of PAI-1 typically employ linear regression to estimate the effects of genetic variants on PAI-1 levels, but PAI-1 is not normally distributed, even after transformation. Therefore, alternative statistical methods may provide greater power to identify important genetic variants. Additionally, most genetic studies of PAI-1 have been performed on populations of European descent, limiting the generalizability of their results. We analyzed >30,000 variants for association with PAI-1 in a Ghanaian population, using median regression, a non-parametric alternative to linear regression. Three variants associated with median PAI-1, the most significant of which was in the gene arylsulfatase B (ARSB) (p = 1.09 x 10⁻⁷). We also analyzed the upper quartile of PAI-1, the most clinically relevant part of the distribution, and found 19 SNPs significantly associated in this quartile. Of note an association was found in period circadian clock 3 (PER3). Our results reveal novel associations with median and elevated PAI-1 in an understudied population. The lack of overlap between the two analyses indicates that the genetic effects on PAI-1 are not uniform across its distribution. They also provide evidence of the generalizability of the circadian pathway’s effect on PAI-1, as a recent meta-analysis performed in Caucasian populations identified another circadian clock gene (ARNTL).

The Effect of PAI-1 4G/5G Polymorphism and Clinical Factors on Coronary Artery Occlusion in Myocardial Infarction

Objective. Data on the impact of PAI-1-675 4G/5G genotype for fibrinolysis during myocardial infarction are inconsistent. The aim of our study was to evaluate the association of clinical and genetic (PAI-1-675 4G/5G polymorphism) factors with coronary artery occlusion in patients with myocardial infarction. Materials and Methods. PAI-1-675 4G/5G detection was achieved by using Sanger sequencing in a sample of patients hospitalized for stent implantation due to myocardial infarction. We categorized the patients into two groups: patients with coronary artery occlusion and patients without coronary artery occlusion according to angiographic evaluation. Results. We identified n = 122 (32.4%) 4G/4G, n = 186 (49.5%) 4G/5G, and n = 68 (18.1%) 5G/5G PAI-1 genotype carriers. Univariate and multivariate analysis showed that only the 4G/5G genotype was associated with coronary artery occlusion (OR: 1.656 and 95% CI: 1.009–2.718, p = 0.046). Conclusions. Our results showed that carriers of PAI-1 4G/5G genotype with myocardial infarction have increased odds of coronary artery occlusion more than 1.6 times in comparison to the carriers of homozygous genotypes.

Genetic polymorphism rs6922269 in the MTHFD1L gene is associated with survival and baseline active vitamin B12 levels in post-acute coronary syndromes patients

Background and Aims

The methylene-tetrahydrofolate dehydrogenase (NADP+ dependent) 1-like (MTHFD1L) gene is involved in mitochondrial tetrahydrofolate metabolism. Polymorphisms in MTHFD1L, including rs6922269, have been implicated in risk for coronary artery disease (CAD). We investigated the association between rs6922269 and known metabolic risk factors and survival in two independent cohorts of coronary heart disease patients.

Methods and Results

DNA and plasma from 1940 patients with acute coronary syndromes were collected a median of 32 days after index hospital admission (Coronary Disease Cohort Study, CDCS). Samples from a validation cohort of 842 patients post-myocardial infarction (PMI) were taken 24–96 hours after hospitalization. DNA samples were genotyped for rs6922269, using a TaqMan assay. Homocysteine and active vitamin B12 were measured by immunoassay in baseline CDCS plasma samples, but not PMI plasma. All cause mortality was documented over follow-up of 4.1 (CDCS) and 8.8 (PMI) years, respectively. rs6922269 genotype frequencies were AA n = 135, 7.0%; GA n = 785, 40.5% and GG n = 1020, 52.5% in the CDCS and similar in the PMI cohort. CDCS patients with AA genotype for rs6922269 had lower levels of co-variate adjusted baseline plasma active vitamin B12 (p = 0.017) and poorer survival than patients with GG or GA genotype (mortality: AA 19.6%, GA 12.0%, GG 11.6%; p = 0.007). In multivariate analysis, rs6922269 genotype predicted survival, independent of established covariate predictors (p = 0.03). However the association between genotype and survival was not validated in the PMI cohort.

Conclusion

MTHFD1L rs6922269 genotype is associated with active vitamin B12 levels at baseline and may be a marker of prognostic risk in patients with established coronary heart disease.

Identifying potential functional impact of mutations and polymorphisms: linking heart failure, increased risk of arrhythmias and sudden cardiac death

Researchers and clinicians have discovered several important concepts regarding the mechanisms responsible for increased risk of arrhythmias, heart failure, and sudden cardiac death. One major step in defining the molecular basis of normal and abnormal cardiac electrical behavior has been the identification of single mutations that greatly increase the risk for arrhythmias and sudden cardiac death by changing channel-gating characteristics. Indeed, mutations in several genes encoding ion channels, such as SCN5A, which encodes the major cardiac Na⁺ channel, have emerged as the basis for a variety of inherited cardiac arrhythmias such as long QT syndrome, Brugada syndrome, progressive cardiac conduction disorder, sinus node dysfunction, or sudden infant death syndrome. In addition, genes encoding ion channel accessory proteins, like anchoring or chaperone proteins, which modify the expression, the regulation of endocytosis, and the degradation of ion channel a-subunits have also been reported as susceptibility genes for arrhythmic syndromes. The regulation of ion channel protein expression also depends on a fine-tuned balance among different other mechanisms, such as gene transcription, RNA processing, post-transcriptional control of gene expression by miRNA, protein synthesis, assembly and post-translational modification and trafficking. The aim of this review is to inventory, through the description of few representative examples, the role of these different biogenic mechanisms in arrhythmogenesis, HF and SCD in order to help the researcher to identify all the processes that could lead to arrhythmias. Identification of novel targets for drug intervention should result from further understanding of these fundamental mechanisms.

Association of tissue plasminogen activator and plasminogen activator inhibitor polymorphism with myocardial infarction: a meta-analysis

INTRODUCTION

To investigate whether t-PA Alu repeat insertion/deletion (I/D) and PAI-1 4G/5G genetic variations are associated with the risk of MI.

METHODS

We conducted a meta-analysis to assess the association between the t-PA I/D and PAI-1 4G/5G polymorphisms and risk of MI. We also performed subgroup analyses based on ethnicity (Caucasian, Asian, and African), gender and age. Forty one eligible studies including 12,461 cases and 14,993 controls were identified to evaluate the impact of PAI-1 4G/5G polymorphism on MI. Seven studies investigated the relationship between t-PA I/D and MI.

RESULTS

This meta-analysis revealed that the PAI-1 4G allele (4G/4G and 4G/5G genotype) was associated with an increased risk of MI compared with the 5G allele in the overall population (OR=1.094, 95% CI=1.021 - 1.172, p=0.011). The relative risks of MI for 4G/4G genotype was increased when compared to 5G/5G genotype and 5G allele, with odds ratio at 1.157 (95% CI 1.015 - 1.320, p=0.029) and 1.126 (95% CI =1.015 - 1.249, p=0.025). However, the results show that the 4G/5G polymorphism risk for MI was not associated with ethnicity stratification as Caucasian, Asian or African population. No substantial differences in the genotype distributions were observed in the MI group and control group along the lines of gender and age. After multivariable analysis t-PA I/D polymorphism showed no consistent association with MI.

CONCLUSIONS

This study suggests that the 4G/5G polymorphism of PAI-1 may be a risk factor for MI in overall populations.

Plasminogen activator inhibitor-1 4G/5G gene polymorphism and coronary artery disease in the Chinese Han population: a meta-analysis

Background

The polymorphism of plasminogen activator inhibitor-1 (PAI-1) 4G/5G gene has been indicated to be correlated with coronary artery disease (CAD) susceptibility, but study results are still debatable.

Objective and Methods

The present meta-analysis was performed to investigate the association between PAI-1 4G/5G gene polymorphism and CAD in the Chinese Han population. A total of 879 CAD patients and 628 controls from eight separate studies were involved. The pooled odds ratio (OR) for the distribution of the 4G allele frequency of PAI-1 4G/5G gene and its corresponding 95% confidence interval (CI) was assessed by the random effect model.

Results

The distribution of the 4 G allele frequency was 0.61 for the CAD group and 0.51 for the control group. The association between PAI-1 4G/5G gene polymorphism and CAD in the Chinese Han population was significant under an allelic genetic model (OR = 1.70, 95% CI = 1.18 to 2.44, P = 0.004). The heterogeneity test was also significant (P<0.0001). Meta-regression was performed to explore the heterogeneity source. Among the confounding factors, the heterogeneity could be explained by the publication year (P = 0.017), study region (P = 0.014), control group sample size (P = 0.011), total sample size (P = 0.011), and ratio of the case to the control group sample size (RR) (P = 0.019). In a stratified analysis by the total sample size, significantly increased risk was only detected in subgroup 2 under an allelic genetic model (OR = 1.93, 95% CI = 1.09 to 3.35, P = 0.02).

Conclusions

In the Chinese Han population, PAI-1 4G/5G gene polymorphism was implied to be associated with increased CAD risk. Carriers of the 4G allele of the PAI-1 4G/5G gene might predispose to CAD.

Role of fibrinolytic parameters and plasminogen activator inhibitor 1 (PAI-1) promoter polymorphism on premature atherosclerosis in SLE patients

Premature atherosclerosis has been recognized as a major co-morbid condition in systemic lupus erythematosus (SLE). In this study, we aimed to investigate the effect of tPA (tissue plasminogen activator) and PAI-1 (plasminogen activator inhibitor) antigen concentrations and 4G/5G polymorphism of the PAI-1 gene on the development of atherosclerosis in SLE patients. One hundred and six SLE patients, 28 Takayasu arteritis (TA) patients and 98 healthy control subjects (HCs) were studied. PAI-1 and tPA antigen levels were measured by ELISA method. PAI-1 gene polymorphism was determined by using allele-specific PCR method. SLE patients had a significantly higher frequency (22.6%) of plaque (p = 0.01) and higher IMT (p=0.04) compared with HCs respectively. Only age at disease onset was associated with plaque formation in multivariate regression analysis (p = 0.001). Plasma tPA ag levels in SLE patients were significantly higher compared with HCs (p = 0.005) and PAI-1 ag levels were significantly higher compared with TA patients (p = 0.03). There were no significant differences between study groups in both genotype distribution and allele frequencies of PAI-1 gene, but SLE patients with 4G/4G genotype had higher IMT (p = 0.02) calcium scoring (p = 0.006) compared with 4G5G/5G5G genotypes. The present study suggests that measuring fibrinolytic parameters would have little additional benefit beyond traditional and novel risk factors in predicting coronary artery disease (CAD).

Association of PAI-1 4G/5G and -844G/A gene polymorphisms and changes in PAI-1/tissue plasminogen activator levels in myocardial infarction: a case-control study

BACKGROUND

Myocardial infarction (MI) is induced by acquired and inherited risk factors, including the plasminogen activator inhibitor-1 (PAI-1) -844G/A and -675G/A (4G/5G) gene variants.

OBJECTIVE

The aim of this study was to investigate the association between PAI-1-844G/A and 4G/5G polymorphisms and changes in PAI-1 and tissue plasminogen activator (tPA) levels in MI in a Tunisian population.

METHODS

This was a case-control study involving 305 patients with MI and 328 unrelated healthy controls. PAI-1 genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (RFLP) (-844G/A) or by polymerase chain reaction-allele specific amplification. PAI-1 and tPA levels were assayed by serological assays.

RESULTS

In contrast to tPA levels, mean plasma PAI-1 antigen levels were higher in cases than in control subjects. The elevation in PAI-1 levels was more pronounced in -844A and 4G allele carriers. Significantly higher frequencies of (mutant) 4G and -844A alleles and 4G/4G and -844A/-844A genotypes, and corresponding lower frequencies of (wild-type) 5G and -844G alleles and 5G/5G and -844G/-844G genotypes were seen in patients than in controls. Increased prevalence of 4G/-844A and decreased prevalence of 5G/-844G haplotypes were seen in patients than in controls, thereby conferring a susceptibility and protective nature to these haplotypes, respectively. Regression analysis confirmed the independent association of 4G/4G and -844A/A with MI, after controlling for a number of covariates.

CONCLUSION

This study indicated that the risk of MI was notably high in 4G and -844A carriers with elevated plasma PAI-1 and were associated with reduced tPA levels.

Angiotensin-converting enzyme 2 A1075G polymorphism is associated with survival in an acute coronary syndromes cohort

BACKGROUND

Polymorphisms of the angiotensin-converting enzyme 2 (ACE2) gene, which is located on the X chromosome, have been associated with hypertension and left ventricular hypertrophy in previous studies. We tested the hypothesis that the rare allele of an ACE2 gene polymorphism was associated with risk factors for and adverse outcome after acute coronary syndrome (ACS) events.

METHODS

Patients (n = 1,042) were recruited after admission for an ACS event and were genotyped for the A1075G polymorphism of the angiotensin-converting enzyme 2 gene. This genetic marker was tested for association with baseline measurements, echocardiographic measurements, and clinical outcome, over a median 2.19 years follow-up. As the ACE2 gene is X-linked, analyses were performed separately for males and females. Patients were predominantly of European ethnicity (90.1%).

RESULTS

The A1075 allele was significantly associated with covariate-adjusted mortality in male patients (hazard ratio 1.95, 95% CI 1.10-3.46, P = .047) but not unadjusted (hazard ratio 1.14, 95% CI 0.736-1.76, P = .56). The G1075 (P < .035) allele was more frequent in patients of Maori compared to European ancestry. E/E', an echocardiographic index of left ventricular diastolic function and filling pressure, was higher in males in the A1075 group (G allele group 10.5 [95% CI 10.0-11.0], A allele group 11.4 [95% CI 10.8-12.1], P = .024). A1075 genotype was significantly associated with male survival in the absence of (mortality: A 12.8%, n = 39; G 29.2%, n = 48; P = .037) but not in the presence of beta-blocker treatment (mortality: A 13.5% n = 273; G 8.2% n = 304, P = nonsignificant).

CONCLUSIONS

The A1075 allele was associated with covariate-adjusted mortality in male patients.

Polymorphisms in coagulation factors and the risk of recurrent cardiovascular events in men after a first myocardial infarction

BACKGROUND

The aim of this study was to examine whether genetic predisposition to high levels of coagulation factors influences the risk of developing fatal and non-fatal arterial cardiovascular events in men with a first myocardial infarction (MI).

METHODS

We performed a cohort study among 542 MI patients with a mean age of 56 years (range 32-70 years) at the time of the event. All of the men had a first MI between 1990 and 1996 and were followed until 1 September 2004. DNA was analyzed for polymorphisms of fibrinogen, prothrombin (factor II), factor V, factor VII and plasminogen activator inhibitor type 1, all of which are associated with gain of function of the protein. We collected information from hospital files and general practitioners on the occurrence of major arterial events.

RESULTS

In total, 254 major arterial cardiovascular events occurred during a median follow-up period of 11 years (range 0.2-15 years). The point estimates of the relative rates (RRs) of these events for the variant genotypes were all between 0.7 and 1.1 except for the prothrombin 20210A mutation: RR 1.8 (95% confidence interval 0.8-4.1).

CONCLUSION

These findings suggest that there is no association between coagulation factor polymorphisms, previously associated with plasma levels, and the risk of recurrent cardiovascular events.

Genomics, heart failure and sudden cardiac death

Sudden cardiac death (SCD) is among the most common causes of death in developed countries throughout the world. Despite decreased overall cardiac mortality, SCD rates appear to be increasing in concert with escalating global prevalence of coronary disease and heart failure, the two major conditions predisposing to SCD. This unfavorable trend is a consequence of our inability to identify those who will die suddenly from lethal ventricular arrhythmias and to develop effective therapies for all populations at risk. The known risk factors for SCD lack the predictive power needed to generate preventive strategies for the large number of fatal arrhythmic events that occur among lower-risk subsets of the population. Even among recognized high-risk subsets, prediction of SCD remains challenging. With the exception of the implantable cardioverter defibrillator (ICD) there are few effective strategies for the prevention and treatment of SCD. This article discusses the prospect of genomic science as an approach to the identification of patients at high-risk for SCD. While the final common pathway for SCD is malignant ventricular arrhythmias, there are many potential contributors, pathways, and mechanisms by which common genetic variants (polymorphisms) could affect initiation and propagation of life-threatening cardiac arrhythmias. Recent advances in genomic medicine now provide us with novel approaches to both identify candidate genes/pathways and relatively common polymorphisms which may predispose patients to increased risk for SCD. Improved understanding of the relationship between common polymorphisms and SCD will not only improve risk stratification such that ICDs can be targeted to those patients most likely to benefit from them but also provide new insight into the pathophysiology of SCD.

The effect of the plasminogen activator inhibitor-1 4G/5G polymorphism on the thrombotic risk

Plasminogen activator inhibitor (PAI-1), is the central component of the fibrinolytic system. A deletion/insertion (4G/5G) polymorphism in the promoter region of the PAI-1 gene has been correlated with levels of plasma PAI-1. The 4G allele is associated with higher levels of PAI-1, and might increase the risk for intravascular thrombosis. However, the contribution of this genetic variant to the risk for thrombosis, both arterial and venous, has not been clearly established. A broad spectrum of findings regarding the effect of the 4G allele on thrombotic risk in different target organs has been reported. Our aim is to summarize the variable influence of this polymorphism on thrombotic events in different tissues or organs and explain the underlying mechanisms accounting for these differences.

Association of gene polymorphisms for plasminogen activators with alveolar bone loss

BACKGROUND AND OBJECTIVE

The plasminogen activating system is a protease/inhibitor system central to extracellular matrix remodeling with a suggested role in periodontal disease pathology. A few studies have reported polymorphisms in the genes of plasminogen activator inhibitors to be associated with periodontal disease severity. Two gene polymorphisms - a BamHI restriction fragment length polymorphism in the urokinase plasminogen activator gene (uPA) and a HindIII restriction fragment length polymorphism in the plasminogen activator inhibitor type 1 gene (PAI-1) - have been associated with conditions having a vascular component, and our objective was to assess the association of these gene polymorphisms with alveolar bone loss in chronic periodontal disease of adults.

MATERIAL AND METHODS

Genotype was determined by polymerase chain reaction amplification of whole blood, pertinent histories were obtained by interview, and alveolar bone loss was assessed from current radiographs.

RESULTS

In 77 elderly patients with a normal distribution of alveolar bone loss, we demonstrated a significant association between levels of alveolar bone loss and these polymorphisms in the uPA and PAI-1 genes. Controlling for the contributions of smoking or diabetes to periodontal bone loss, estimated odds ratios for predicting lower levels of alveolar bone loss, associated with a greater degree of periodontal health, were strongest when defined by the concurrent presence of a homozygous urokinase plasminogen activator genotype and the nuclease-sensitive plasminogen activator inhibitor type 1 (HindIII) allele (odds ratio = 2.6; 95% confidence interval: 5.8-1.3).

CONCLUSION

The urokinase plasminogen activator (BamHI) and plasminogen activator inhibitor type 1 (HindIII) genotypes may serve as useful markers for heritability of bone loss associated with periodontal disease.

Plasminogen activator inhibitor-1 4G4G genotype is associated with myocardial infarction but not with stable coronary artery disease

BACKGROUND

A case control study was conducted to test the hypothesis that plasminogen activator inhibitor type-1 (PAI-1) 4G/5G gene polymorphism confers an increased risk for myocardial infarction (MI) in patients with known coronary atherosclerosis.

METHODS

One hundred fifty-six consecutive patients who presented with acute MI and 111 stable coronary artery disease (SCAD) patients with documented critical coronary artery stenoses were prospectively enrolled. PAI-1 4G/5G gene polymorphism and conventional atherosclerotic risk factors were studied in all patients. PAI-1 4G/5G gene polymorphism was studied in another 281 healthy blood bank donors.

RESULTS

The frequency 4G4G genotype was significantly higher in the MI group as compared to SCAD group (32.7% vs. 15.3%, P = 0.001) while it was not statistically significant between MI and healthy control groups (32.7% vs. 26.0%, P = 0.136). Comparing with healthy controls SCAD group had significantly lower frequency of 4G4G genotype (P = 0.024). In comparison with SCAD group PAI-1 4G/4G genotype, male sex and smoking habits favored to MI in univariate analysis with a P value of less than 0.2. These variables were included in multivariate regression model to estimate the associated risk for MI. PAI-1 4G/4G genotype was the only independent variable (OR 2.67, 95%CI 1.43-4.96, P = 0.002) associated with MI in this regression model. Comparing with healthy control group 4G4G genotype was not associated with MI (OR 1.38, 95%CI 0.90-2.12). However, presence of 4G4G genotype had a protective effect against development of SCAD (OR 0.52, 96%CI 0.29-0.92).

CONCLUSION

Compared to patients with critical coronary stenoses, PAI-1 4G/4G genotype was found to be an independent predictor for development of MI in this population. PAI-1 4G4G genotype have a protective effect against development of high grade stable coronary stenoses.

Prognostic value of PAI1 in invasive breast cancer: evidence that tumor-specific factors are more important than genetic variation in regulating PAI1 expression

Plasminogen activator inhibitor-1 (PAI1) can promote cancer progression, and its protein expression in tumors is an independent indicator of poor prognosis in many forms of cancer. Here, we show that high PAI1 mRNA levels also predict for shorter overall survival in two independent breast cancer data sets, highlighting the importance of its transcriptional regulation. The -675insG (4G/5G) single-nucleotide polymorphism in the PAI1 gene promoter has been shown to influence PAI1 transcription, with the 4G allele eliciting higher reporter gene expression in vitro and higher levels of circulating PAI1 in vivo. Nevertheless, its genotypic distribution in 2,539 British women with invasive breast cancer was virtually identical to that seen in 1,832 matched controls (P = 0.72), and annual mortality rates for 4G4G, 4G5G, and 5G5G cases were 2.6%, 2.8%, and 3.1% per year, respectively (P = 0.10). Thus, there was no association with breast cancer incidence or outcome, and in a separate set of breast cancers, the 4G/5G single-nucleotide polymorphism showed no association with PAI1 mRNA expression (P = 0.85). By contrast, connective tissue growth factor (CTGF), which can regulate PAI1 expression in culture, was associated with PAI1 expression in three independent cohorts (P << 0.0001). In addition, PAI1 gene copy number differences in the tumors were correlated with PAI1 mRNA expression (P = 0.0005) and seemed to affect expression independently of CTGF. Thus, local factors, such as CTGF and genomic amplification, seem to be more important than germ line genetic variation in influencing PAI1 expression and its untoward effects in breast cancer.

Elevated Plasma Plasminogen Activator Inhibitor Type-1 is an Independent Predictor of Coronary Microvascular Dysfunction in Hypertension

BACKGROUND

Elevated plasma plasminogen activator inhibitor-1 (PAI-1) is related to cardiovascular events, but its role in subclinical coronary microvascular dysfunction remains unknown. Thus, in the present study it was investigated whether elevated plasma PAI-1 activity is associated with coronary microvascular dysfunction in hypertensive patients.

METHODS AND RESULTS

Thirty patients with untreated essential hypertension and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography. Clinical variables associated with atherosclerosis (low-density lipoprotein-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, homeostasis model assessment (HOMA-IR), and PAI-1 activity) were assessed to determine their involvement in coronary microvascular dysfunction. Adenosine triphosphate (ATP)-induced hyperemic MBF and coronary flow reserve (CFR) were significantly lower in hypertensive patients than in healthy controls (ATP-induced MBF: 2.77+/-0.82 vs 3.49+/-0.71 ml x g(-1) x min(-1); p<0.02 and CFR: 2.95 +/-1.06 vs 4.25+/-0.69; p<0.001). By univariate analysis, CFR was positively correlated with HDL-cholesterol (r=0.46, p<0.02), and inversely with HOMA-IR (r=-0.39, p<0.05) and PAI-1 activity (r=-0.61, p<0.001). By multivariate analysis, elevated PAI-1 activity remained a significant independent determinant of diminished CFR.

CONCLUSIONS

Elevated plasma PAI-1 activity was independently associated with coronary microvascular dysfunction, which suggests that plasma PAI-1 activity is an important clue linking hypofibrinolysis to the development of atherosclerosis.

Effects of VLDL and Remnant Particles on Platelets

There is a considerable body of evidence supporting an association between hypertriglyceridaemia, a hypercoagulable state and atherothrombosis. A disorder of triglyceride metabolism is a key feature of the metabolic syndrome that increases risk of both ischaemic heart disease and type 2 diabetes approximately 3-fold. An increasing prevalence of obesity and metabolic syndrome is likely to contribute markedly to the prevalent ischaemic heart in the foreseeable future, and therefore it is crucial to understand mechanisms linking hypertriglyceridaemia and a hypercoagulable state. Activation of platelets and the coagulation cascade are intertwined. VLDL and remnant lipoprotein concentrations are often increased with the metabolic syndrome. These lipoproteins have the capacity to activate platelets and the coagulation pathway, and to support the assembly of the prothrombinase complex. VLDL also upregulates expression of the plasminogen activator inhibitor-1 gene and plasminogen activator inhibitor-1 antigen and activity, a process accompanied by platelet aggregation and clot formation. The surface membrane of activated platelets also supports the assembly and activity of the prothrombinase complex, resulting in further thrombin generation and amplification of the coagulation cascade. Fibrinolysis is also less efficient when thrombin is generated. Thrombin induces thrombin activatable fibrinolysis inhibitor. Thrombin activatable fibrinolysis inhibitor is a carboxypeptidase that cleaves the carboxylic lysine residues on fibrin, thereby abolishing the critical binding site for tPA-plasminogen decreasing plasmin formation. Thus the evidence is supportive of dysregulated coagulation, and impaired fibrinolysis with a predisposition to atherothrombosis, in conditions such as the metabolic syndrome, in which there are increased concentrations of VLDL and remnant lipoproteins. The purpose of this review is to describe the current evidence supporting a procoagulant state induced by VLDL and remnant lipoproteins. The role of these lipoprotein classes in (1) platelet activation; (2) the intrinsic coagulation cascade, and (3) clot formation and fibrinolysis is discussed.

Genomics in sudden cardiac death

Sudden cardiac death (SCD) remains a public health problem of major magnitude. Contrary to earlier expectations, and despite decreased overall cardiac mortality, SCD rates appear to be rising in concert with escalating global prevalence of coronary disease and heart failure, the two major conditions predisposing to SCD. With the exception of the implantable defibrillator, there are few effective approaches to SCD prevention and even fewer clues concerning patient phenotypes predisposed to life-threatening arrhythmias. Clinical variables such as ejection fraction predict mortality but are not sensitive enough to identify many high SCD risk patients. The predictive power of autonomic dysregulation and markers such as lipid levels, hypertension, diabetes, and smoking is quite low in subclinical heart disease, the population in which the majority of SCDs occur. This review addresses advances in genomic science applicable to the SCD public health problem in both rare and common forms of heart disease. These include novel bioinformatic approaches to both identify candidate genes/pathways and identify previously unknown functional genetic elements, as well as methods to comprehensively screen these elements. We also discuss the possibility of applying high-density genome-wide SNP analyses to examine genetic contributions to arrhythmia susceptibility in community-based, case-control studies of common forms of SCD. The development of novel strategies to identify contributors to susceptibility in common cardiac phenotypes is most likely to lead to new and relevant therapeutic targets for SCD.

Relationships between fibrinogen, plasminogen activator inhibitor-1, and their gene polymorphisms in current smokers with essential hypertension

BACKGROUND

To elucidate the role of some haemostatic gene polymorphisms and environmental factors, we studied fibrinogen (Fb), plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (t-PA) levels with respect to Fb G455A and PAI-1 4G/5G gene polymorphisms in smokers and nonsmokers with essential hypertension.

MATERIAL AND METHODS

The study was done in 90 patients (including 30 smokers) with essential hypertension (HT) and 40 controls (including 8 smokers). Fb and PAI-1 genotypes were PCR identified. The groups did not differ significantly as to genotype frequencies.

RESULTS

When allele A455 carriers were compared, HT patients had significantly higher Fb (p=0.015) and t-PA levels (p=0.013). Comparison of 4G allele carriers (4G/4G homozygotes) revealed significantly higher Fb (p=0.045), PAI-1 (p=0.009), and t-PA levels (p=0.007) in HT patients than controls. Interactions of Fb and PAI-1 gene polymorphisms with smoking were disclosed in HT patients only. Allele A455-carrying HT smokers compared with nonsmokers had significantly higher t-PA (12.1 +/- 5.8 vs. 7.4 +/- 3.1 ng/ml; p=0.002) and tendency to higher Fb (3.36 +/- 0.74 vs. 2.95 +/- 0.70 g/l; p=0.075) levels. Higher Fb levels were disclosed in 4G/4G smokers than nonsmokers (3.31 +/- 0.81 vs. 2.84 +/- 0.85 g/l; p=0.064). Finally, in smokers, significantly higher levels of PAI-1 were found in 4G/4G (42.1 +/- 29.4 ng/ml) as compared with 4G/5G (18.6 +/- 13.7 ng/ml; p=0.025) and 5G/5G (14.4 +/- 10.8 ng/ml; p=0.044) genotypes.

CONCLUSIONS

Smoking potentiates the prothrombotic effect of allele A455 and PAI-1 4G/4G genotype in untreated essential hypertension, reflected by increased levels of haemostatic risk factors and accelerated progression of cardiovascular diseases.

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.

The genetics of atherothrombotic disorders: a clinician's view

The development of coronary artery disease is dependent on the interaction of multiple biochemical pathways that lead to the development of plaque in the arterial wall and ultimately plaque instability, plaque rupture and thrombosis. The latter stages lead to vascular obstruction, tissue death and the final phenotype of myocardial infarction. Hemostasis gene association studies of atherothrombotic disorders have been unrewarding, with largely underpowered studies reporting inconsistent results. Clinical studies such as the Multiple Risk Factor Intervention Trial clearly indicate that clustering of classical risk increases the likelihood of myocardial infarction, and the addition of diabetes mellitus to the risk profile exponentially increases the risk of a vascular event. The development of insulin resistance is considered to be a pivotal event in vascular risk with associated clustering of dysglycemia, hyperinsulinemia, systolic hypertension, raised triglyceride and low high-density lipoprotein cholesterol. Additionally, elevated levels of plasminogen activator inhibitor-1, factor (F)VII, FXII, fibrinogen and tissue plasminogen activator occur with insulin resistance to create an atherothrombotic risk cluster. Heritability studies of insulin resistance and the vascular risk profile demonstrate genetic pleitropy between diabetes and vascular risk, which indicate that common genes have an important role. Increasingly, it is felt that inflammation underpins both diabetes and cardiovascular disease and that the expression of the final phenotype(s) may depend on complex gene-environment interactions with regulatory genes, including those for nuclear transcription factors and RNA-binding proteins. The complexity of coronary artery disease and the risk factor interactions make it unlikely that genetic epidemiology will identify genes involved in these processes without a better understanding of environmental influences.

The 4G5G polymorphism in the gene for PAI-1 and the circadian oscillation of plasma PAI-1

Plasminogen activator inhibitor type I (PAI-1) antigen concentrations follow a circadian oscillation peaking in the morning. Some individuals show no apparent circadian rhythm, while others show up to a 10-fold variation in PAI-1 over 24 hours. Results from experimental studies suggest that a polymorphism in the promoter of the gene for PAI-1 (4G5G) directly influences the circadian expression of the PAI-1 gene. We studied whether the diurnal variation of PAI-1 antigen differs for the genotypes of the 4G5G polymorphism. A population-based, cross-sectional study was performed among 263 subjects selected from the Rotterdam Study, a population-based cohort of 7983 men and women aged 55 years and older. The 4G allele was associated with a more pronounced circadian expression of PAI-1 antigen. Morning PAI-1 antigen concentrations were 79 ng/mL (95% confidence interval [CI], 68-92) in subjects homozygous for 4G, 62 ng/mL (95% CI, 54-72) in heterozygous subjects, and 59 ng/mL (95% CI, 49-71) in subjects homozygous for 5G. While respective PAI-1 antigen concentrations in the afternoon were 40 ng/mL (95% CI, 33-49), 41 ng/mL (95% CI, 37-47), and 40 ng/mL (95% CI, 49-71). These findings suggest that the morning increase in PAI-1 antigen concentration is more pronounced among subjects homozygous for the 4G allele compared with the morning increase among the other genotypes. Additionally, these findings show that homozygosity for the 4G allele is associated with increased PAI-1 levels during the morning only.

Effects of coagulation Factor VII polymorphisms on the coronary artery disease in Japanese: Factor VII polymorphism and coronary disease

We investigated the relationships among Factor VII coagulant activity (FVIIc), genetic polymorphisms of Factor VII (FVII) and coronary artery disease (CAD) in 380 unrelated Japanese individuals (mean 64 years) who underwent coronary angiography and whose cholesterol levels were within normal range. CAD subjects were defined as those in whom one of the three major coronary arteries showed >50% narrowing after nitroglycerin administration. FVIIc was measured and the following polymorphisms of FVII were determined: R353Q polymorphism (M1, M2 alleles), -323 0/10 bp polymorphism (0, 10 alleles), hypervariable region 4 of intron 7 (HVR4; H5, H6, H7 alleles). FVIIc was slightly lower in M1M2/M2M2 than M1M1 (89.5+/-8.9%, 93.4+/-17.8%). Those with M2 and/or 10 allele have less chance of developing CAD (M2: OR 0.36, 95% CI 0.18-0.69, 10: OR 0.50, 95% CI 0.26-0.97). However, both alleles did not associate with myocardial infarction (MI). HVR4 was unrelated with CAD, nor with MI. In conclusion, M2 and/or 10 allele has protective effects on the developing CAD in individuals with a normal cholesterol level.

Interaction of hemostatic genetics with hormone therapy: new insights to explain arterial thrombosis in postmenopausal women

Genetic variants of key hemostatic mediators increasingly have been proposed as risk factors for atherothrombosis. The Hormone and Estrogen/Progestin Replacement Study group recently reported that the initiation of estrogen replacement in postmenopausal women with known coronary heart disease is associated with an early increase in cardiovascular events. A putative genetic susceptibility factor has been proposed a potential mediator of this increased event risk. This review outlines the recent literature to support the premise for this important proposal. Genetic profiling has great potential to improve the safety and efficacy of individualized pharmacotherapy in postmenopausal women and other at-risk populations for the prevention of cardiovascular disease.

Genetic variation in coagulation and fibrinolytic proteins and their relation with acute myocardial infarction: a systematic review

BACKGROUND

It is pathophysiologically conceivable that genetic variations in coagulation and fibrinolytic proteins are associated with the risk of myocardial infarction. Methods and Results- We performed a literature search to identify published case-control studies correlating the factor V Leiden or prothrombin G20210A mutations or fibrinogen G-455A or plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphisms with the risk of myocardial infarction. Studies were included only if they used solid diagnostic criteria and complied with published methodological criteria. A common OR with corresponding 95% CI was calculated for the risk of myocardial infarction in a fixed-effect model according to Mantel-Haenszel. The factor V Leiden and prothrombin G20201A mutations did not significantly correlate with myocardial infarction (OR 1.26, 95% CI 0.94 to 1.67, P=0.12 and OR 0.89, 95% CI 0.59 to 1.35, P=0.6, respectively). Inclusion of the studies that investigated young patients (<55 years) made the association significant for factor V Leiden (OR 1.29, 95% CI 1.03 to 1.61, P=0.02). Homozygosity for the fibrinogen -455A allele was significantly associated with a decreased risk of myocardial infarction (OR 0.66, 95% CI 0.44 to 0.99, P=0.04), whereas the PAI-1 4G4G genotype was significantly associated with increased risk (OR 1.20, 95% CI 1.04 to 1.39, P=0.04).

CONCLUSIONS

Associations between these genetic variations and myocardial infarction were weak or absent. In the absence of clinical implications, our results indicate that screening of patients with myocardial infarction for these genetic variations is not warranted.

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.

The 4G/5G promotor polymorphism of the plasminogen activator inhibitor-1 gene and late lumen loss after coronary stent placement in smoking and nonsmoking patients

BACKGROUND

Instent restenosis remains a significant clinical problem. Identification of patients at risk for instent restenosis may allow selection of individualized appropriate therapeutic approaches. Genetic polymorphisms have been suggested to be associated with the risk of instent restenosis. Smoking is known to influence hemostatic parameters.

HYPOTHESIS

This study investigated the influence of the 4G/5G promotor polymorphism of the plasminogen activator inhibitor type I (PAI-1) gene on instent restenosis in smoking and nonsmoking patients.

METHODS

In all, 300 consecutive patients (133 nonsmoking; 167 smoking) with elective coronary stent placement and 6-month angiographic follow-up were studied. Quantitative coronary angiography and genotyping with polymerase chain reaction analysis were performed in all patients.

RESULTS

Nonsmoking PAI-1 4G/4G carriers showed a significantly greater late lumen loss (n = 38; 0.54 +/- 0.53 mm) compared with nonsmoking PAI-1 4G/5G (n = 68; 0.38 +/- 0.45 mm) or 5G/5G (n = 27; 0.19 +/- 0.23 mm) carriers, analysis of variance (ANOVA) p < 0.001. Smoking patients with the genotypes 4G/4G (n = 46; 0.53 +/- 0.54 mm) and 4G/5G (n = 79; 0.37 +/- 0.41 mm) had a late loss similar to that of nonsmoking patients. Smoking 5G/5G carriers had the highest late loss of all smoking patients (n = 42; 0.63 +/- 0.50); ANOVA p < 0.05; nonsmoking 5G/5G vs. smoking 5G/5G p < 0.001.

CONCLUSION

The promotor polymorphism of the PAI-1 gene has a significant influence on instent restenosis after coronary stent implantation. The 5G/5G genotype predisposes nonsmoking gene carriers to less late lumen loss, whereas in smoking gene carriers this genotype is associated with the greatest late lumen loss. This might be explained by an altered expression pattern of hemostatic parameters.

PAI-I 4G/5G polymorphism and sudden cardiac death in patients with coronary artery disease

The 4G/5G polymorphism of the plasminogen activator inhibitor type I (PAI-I) gene is involved in coronary artery disease (CAD), with the highest risk in 4G/4G homozygotes. The role of PAI-I polymorphism in patients suffering from CAD and history of sudden cardiac death (SCD) has not been addressed yet. We studied the frequency distribution of the PAI-I gene to test the hypothesis that the 4G/4G genotype favors myocardial ischemia and, even in the absence of acute infarction, promotes SCD in patients with CAD.

METHODS

The PAI-I 4G/5G genotypes and PAI-I antigen plasma levels were determined in 97 patients with CAD and a history of SCD treated with an implantable cardioverter defibrillator (ICD) (defibrillator group) comparing to 113 patients with CAD but no history of SCD (control group).

RESULTS

The defibrillator group consisted of significantly more 4G/4G homozygotes and higher PAI-I levels than the control group (44% vs. 24%, 173+/-41 vs. 144+/-49 ng/ml; P<.01). The carriers of 4G allele had a significantly higher risk for SCD (odds ratio (OR) 1.9) with the highest risk in the 4G/4G genotype (OR 3.6, P<.01).

CONCLUSION

These results suggest that the PAI-I 4G/4G genotype is associated with SCD in patients suffering from CAD.

The 4G/5G polymorphism of the type 1 plasminogen activator inhibitor gene and thrombosis in patients with antiphospholipid syndrome

OBJECTIVE

To investigate the relationship between the 4G/5G polymorphism of the type 1 plasminogen activator inhibitor (PAI-1) gene and thrombotic manifestations in patients with antiphospholipid syndrome (APS).

METHODS

We studied a total of 247 patients included in the following 4 groups: 70 patients with primary APS, 104 patients with systemic lupus erythematosus (40 with antiphospholipid antibodies [aPL] and clinical [secondary] APS, 13 with aPL but without clinical APS, and 51 with neither detectable aPL nor a history of thrombosis), 14 asymptomatic individuals with aPL, and 59 patients with thrombosis but without known thrombosis risk factors. A control group of 100 healthy individuals was also analyzed. PAI-1 4G/5G polymorphism was determined by polymerase chain reaction and endonuclease digestion.

RESULTS

The allele frequency of 4G/5G in controls was 0.47/0.53. There were no differences in allele distribution among patient groups or between patients and controls. However, a higher frequency of the 4G allele was observed in APS patients with versus those without thrombosis (0.57 versus 0.39; P < 0.05) (odds ratio [OR] 2.83, 95% confidence interval [95% CI] 1.18-6.76). This higher frequency of the 4G allele was attributable to the higher frequency in patients with versus those without arterial thrombosis (0.64 versus 0.43; P < 0.01) (OR 5.96, 95% CI 1.67-21.32), while patients with venous thrombosis had an allele distribution similar to that of those without venous thrombosis (0.49 versus 0.50; P not significant). There was a trend toward higher PAI-1 antigen and activity levels in APS patients and controls with the 4G/4G genotype, but this did not reach statistical significance.

CONCLUSION

The presence of the 4G allele of the 4G/5G polymorphism of the PAI-1 gene may be an additional risk factor for the development of arterial thrombosis in APS.

Lack of association of a common polymorphism of the plasminogen activator inhibitor-1 gene with coronary artery disease and myocardial infarction

OBJECTIVES

The study was done to assess whether the common polymorphic allele (4G) of the plasminogen activator inhibitor-1 (PAI-1) gene is associated with coronary artery disease (CAD) or myocardial infarction (MI).

BACKGROUND

Impaired fibrinolytic function has been associated with CAD and MI. Plasminogen activator inhibitor-1 plays a central role in intravascular thrombosis and thrombolysis; the common insertion/deletion polymorphism (4G/5G) of PAI-1 has been correlated with altered PAI-1 levels and proposed as a coronary risk factor.

METHODS

Blood was drawn and DNA extracted from 1,353 consenting patients undergoing coronary angiography. The 4G and 5G alleles of PAI-1 were amplified using specific primers. Amplified products were visualized by staining with ethidium bromide after electrophoresis in 1.5% agarose.

RESULTS

Patient age averaged 63.5 (SD 11.7) years; 70% were men, 28% had a history of MI, 66% had severe CAD (>60% stenosis), and 23% had no CAD or MI. Overall, the frequency of the 4G allele was 54.2%, and 78% of patients were 4G carriers. Genotypic distributions were: 4G/4G = 30.1%, 4G/5G = 47.9%, and 5G/5G = 21.8%. Neither carriage of 4G (CAD odds ratio [OR] = 1.08 [0.80 to 1.46], MI OR = 1.11 [0.83 to 1.49]) nor 4G/4G homozygosity (CAD OR = 1.07, MI OR = 0.98) was associated with CAD or MI. In multivariate analyses, risk factors associated with CAD were (in order): gender, age, smoking, diabetes, cholesterol, and hypertension; for MI, they were gender, smoking, and cholesterol.

CONCLUSIONS

A common PAI-1 polymorphism (4G) was not importantly associated with angiographic CAD or history of MI in a Caucasian population. Modest risk (i.e., OR <1.5), especially for MI, or risk in association with other factors, cannot be excluded.

Genetic determinants of arterial thrombosis

This chapter describes examples of genetic variation involved in the function or regulation of a number of haemostatic proteins involved in the thrombotic process. In each case, the data suggest associations between genotype and disease and, particularly in the case of fibrinogen, PAI-1, Factor VII and Factor XIII, there is interaction between genotype and environment in determination of the relevant plasma level, providing a possible explanation for the differential response of individuals to their environment.

Clinical implications of elevated PAI-1 revisited: multiple arterial thrombosis in a patient with essential thrombocythemia and elevated plasminogen activator inhibitor-1 (PAI-1) levels: a case report and review of the literature

Plasminogen activator inhibitor (PAI-1), a member of the serine protein family, is the most active in vivo inhibitor of fibrinolysis induced by plasminogen, tissue plasminogen activator (tPA), and urokinase type plasminogen activator (uPA). While the association between elevated PAI-1 and thrombogenesis has been well studied for several disease processes, including coronary disease, postoperative deep vein thrombosis (DVT), myocardial infarction, malignancy, and diabetes, few studies have concentrated on the correlation between elevated PAI-1 levels and thrombogenesis in patients with myeloproliferative disorders. Essential thrombocythemia (ET), a chronic myeloproliferative disorder, characterized by the overproduction of poorly functioning platelets, is associated with both thrombotic and hemorrhagic life-threatening complications. Although the events resulting in thrombogenesis in such patients may be multifactorial in nature, an association between elevated PAI-1 levels and thrombus formation has been proposed. Herein we present a patient diagnosed with ET complicated by multiple episodes of arterial thrombosis. Elevations in PAI-1 levels were documented repeatedly. The role of elevated PAI-1 when associated with other disease processes is also discussed.