The 4G/4G genotype at nucleotide position -675 in the promotor region of the plasminogen activator inhibitor 1 (PAI-1) gene is less frequent in young patients with minor stroke than in controls

Association of PAI-1 rs1799889 Polymorphism with Susceptibility to Ischemic Stroke: a Huge Meta-Analysis based on 44 Studies

BACKGROUND

the PAI-1 rs1799889 polymorphism has been reported to be associated with susceptibility to ischemic stroke. However, the results of previous studies have been inconsistent or controversial. Hence, we performed a systematic review and meta-analysis to evaluate the association of PAI-1 rs1799889 polymorphism with ischemic stroke risk.

METHODS

A comprehensive literature search was performed on PubMed, Web of Science, Scopus, SciELO, CNKI, and CBD databases up to November 05, 2019. Pooled odds ratio (OR) with 95% confidence interval (CI) were used to access the strength of this association in fixed- or random-effects model.

RESULTS

A total of 44 case-control studies with 8,620 cases and 10,260 controls were selected. Pooled data showed a significant association between PAI-1 rs1799889 polymorphism and ischemic stroke risk in the overall populations (GG vs. AA: OR = 0.791, 95% CI 0.633-0.988, p = 0.039; GA vs. AA: OR = 0.807, 95% CI 0.683-0.953, p = 0.012; and GG+GA vs. AA: OR = 0.795, 95% CI 0.637-0.993, p = 0.043). Subgroup analysis by ethnicity revealed a significant association in Asian and Mixed populations, but not in Caucasians. Moreover, stratified analysis by country of origin revealed an increased risk of ischemic stroke in Chinese populations, but not among Dutch (Netherlands) and Swedish.

CONCLUSIONS

This meta-analysis result suggested that PAI-1 rs1799889 polymorphism was associated with an increased risk of ischemic stroke, especially in Asian and Mixed populations.

Lack of Associations Between PAI-1 and FXIII Polymorphisms and Arterial Ischemic Stroke in Children: A Systematic Review and Meta-Analysis

The role of genetic risk factors for ischemic stroke seems to be in particular significance in pediatric patients. Numerous polymorphic variants of genes encoding proteins, that is, plasminogen activator inhibitor as well as coagulation factors, involved in the coagulation cascade may be related to arterial ischemic stroke (AIS) both in adults and children. We performed systematic review and 2 meta-analyses to assess possible correlations between common plasminogen activator inhibitor (PAI-1) and FXIII polymorphisms and ischemic stroke in children. We searched PubMed to identify available data published before October 2018 using appropriate keywords and inclusion criteria. Finally, 12 case-control studies were included: 8 analyzing PAI-1 polymorphism (600 children with stroke and 2152 controls) and 4-FXIII polymorphism (358 children with stroke and 451 controls). R and Comprehensive Meta-Analysis software were used to analyze the impact of the particular polymorphism in the following models: dominant, recessive, additive, and allelic. No publication bias was observed in both meta-analyses. In case of PAI-1 polymorphism, we observed no relation between 4G4G genotype of 4G allele and ischemic stroke in children. We also demonstrated lack of association between FXIII polymorphism and childhood ischemic stroke. In children with AIS, the PAI-1 and FXIII polymorphisms are not risk factors for the disease.

Association of PAI-1 4G/5G Polymorphism with Ischemic Stroke in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND/AIM

To investigate the association of the genetic polymorphisms of the plasminogen activator inhibitor type 1 (PAI-1) gene with the risk of ischemic stroke (IS) in subjects with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Using a case-control study design, 175 individuals with T2D and IS were enrolled in the case group and 125 patients with T2D without IS were enrolled as controls. The clinical characteristics of the groups were compared, and genotypes were determined by direct DNA sequencing.

RESULTS

Male and hypertensive subjects were higher in the IS group (p = 0.002 and 0.014, respectively). High-density lipoprotein (HDL) and apolipoprotein A1 (APOA1) were lower in the IS group (p = 0.011 and 0.025, respectively); hemoglobin A1c (HbA1c), total homocysteine (tHcy), and FT4 levels were higher in the IS group (p = 0.022, 0.003, and 0.008, respectively). The 4G/4G, 4G/5G, and 5G/5G genotype frequencies were 40.0%, 46.4%, and 13.6% in the control group versus 31.4%, 52.0% and 16.6% in the IS group, respectively. Hypertension (odds ratio [OR] = 1.953, p = 0.020), tHcy (OR = 1.059, p = 0.029), thyroid-stimulating hormone (OR = 0.876, p = 0.039), and the PAI-1 genotype dominant allele model (OR = 1.748, p = 0.047) were associated with IS by multivariate analysis.

CONCLUSION

The PAI-1 genotype dominant allele model was a risk factor for IS in patients with T2DM of Jinan, China.

[New developments in molecularbiological diagnostic]

Today, we have access to excellent and advanced molecular methods that are already widely used. This requires rules to control the quality of the methods as well as the laboratory. Both aspects will be discussed in the article. Following the isolation of nucleic acids they are used for genotyping which allows to address several questions: diagnosis of inherited diseases, inherited predispositions, forensic analyses, identification and typing of bacteria or viruses, elucidation of evolutionary aspects. Importantly, it has to be realized that the type and heterogeneity of phenotypically relevant mutations determines the method used for testing. Today, most laboratories use either PCR analyses or Sanger sequencing for diagnostic applications. However, increasingly next generation sequencing (NGS) is applied. The clinical use of NGS is still very challenging, but we can expect that the switch to regular application of this method will be coming in the very near future. The price for NGS has gone down to approx. USD 1000,- which makes the routine diagnostic use feasible. Nevertheless, several challenges have yet to be solved, such as the processing of the large data volume as well as storage of the data. Supporting data bases exist already and some will be discussed in the article. The understanding of the clinical relevance of many polymorphisms is another issue that has yet to be solved, particularly as in the context of personalized medicine polymorphisms have become increasingly important.

Vascular Genetic Variants and Ischemic Stroke Susceptibility in Albanians from the Republic of Macedonia

BACKGROUND

Acute first-ever ischemic stroke (FIS) is a heterogeneous, polygenic disorder. The contribution of vascular genetic variants as inherited causes of ischemic stroke has remained controversial.

AIM

To examine the association of genetic variants in vascular factors with the occurrence of FIS.

MATERIAL AND METHODS

The current research was performed in a group of 39 patients with FIS (study group) and 102 healthy volunteers (control group). We analyzed the prevalence of vascular genetic variants in following genes: factor V, prothrombin, methylenetetrahydrofolate reductase (MTHFR), factor XIII, plasminogen activator 1, endothelial protein C receptor (EPCR), apolipoprotein B, apolipoprotein E, β-fibrinogen, human platelet antigen 1, angiotensin-converting enzyme (ACE), endothelial nitric oxide synthase (eNOS) and lymphotoxin alpha.

RESULTS

It was found that heterozygous LTA 804C>A and FXIII V34L Leu/Leu were significantly more frequent in patients with FIS than in control group (p = 0.036 and p = 0.017, respectively). The frequency of FXIII V34L Val/Val was significantly lower in patients with FIS than in control group (p = 0.020). Other frequencies of vascular gene variants in patients with FIS and in control group were not significantly different.

CONCLUSIONS

This is the first comprehensive study to present data indicating that polymorphism of vascular genes in the prevalence of acute FIS exists in the Albanian population from the Republic of Macedonia. Variations in these genes have been detected in patients with acute FIS, suggesting that their combination might act in a susceptible or protective manner in this Albanian population.

Blood Biomarkers in Minor Stroke and Transient Ischemic Attack

Minor stroke and transient ischemic attack (TIA) are common disorders with a high rate of subsequent disabling stroke, so the early recognition and management of minor stroke and TIA is of great importance. At the moment, the diagnosis of these disorders is based on neurologic deficits in a stroke-clinician's examination of the patient, supplemented by the results of acute brain imaging. However, high variability in TIA diagnosis has been reported between physicians, even trained vascular neurologists, and image-based diagnostic confirmation is not always readily available. Some patients still have ischemic events despite sustained standard secondary preventive therapy. Blood biomarkers are promising to aid in the diagnosis, risk stratification, and individual treatment of minor stroke and TIA. Some studies are being conducted in this field. This mini-review aims to highlight potential biomarkers for diagnosis and those helpful in predicting the risk of future stroke and the selection of treatment.

Association Between Plasminogen Activator Inhibitor-1 Genetic Polymorphisms and Stroke Susceptibility

The plasminogen activator inhibitor-1 (PAI-1) is a candidate gene for stroke based on PAI-1's crucial role in fibrinolytic system. However, association studies have yielded conflicting results regarding the association between PAI-1 polymorphisms and stroke susceptibility. To further elucidate the putative association, we performed a systematic review and meta-analysis to provide a complete picture of the loci investigated for association of PAI-1 polymorphism with stroke risk and to derive a precise estimation. PubMed, Embase, and China National Knowledge Infrastructure (CNKI) databases were searched until June 2015 to identify eligible studies. Forty data sets from 39 studies with a total of 8336 cases and 14,403 controls were included. The most commonly investigated polymorphism was -675 4G/5G, followed by -844 G/A, 11053 T>G, HindIII C/G, and (CA)n. Overall, our meta-analysis provided evidence for the significant association of PAI-1 4G/5G polymorphism with an increased risk of adult but not pediatric ischemic stroke (adult: 4G/4G vs. 4G/5G + 5G/5G, OR = 1.21, 95 % CI = 1.04-1.42). In the subgroup analysis, significant association was detected in Asians (4G/4G vs. 4G/5G + 5G/5G, OR = 1.45, 95 % CI = 1.14-1.85) but not Caucasians. Moreover, we found that -844 G/A but not 11053 T>G polymorphism was associated with an increased risk of ischemic stroke (-844G/A: A/A vs. G/G: OR = 1.32, 95 % CI = 1.01-1.73). A tendency of PAI-1 4G/5G polymorphism towards a decreased risk of hemorrhagic stroke was observed (4G/4G + 4G/5G vs. 5G/5G, OR = 0.77, 95 % CI = 0.59-1.02, P = 0.066). Future well-designed studies in large well-characterized sample size and presenting results stratified by gender, age, and stroke subtype are warranted.

Biomarkers for arterial and venous thrombotic disorders

The haemostatic system maintains the blood in a fluid state, but allows rapid clot formation at sites of vascular injury to prevent excessive bleeding. Unbalances within the haemostatic system can lead to thrombosis. Inspite of successful research our understanding of the disease pathogenesis is still incomplete. There is great hope that genetic, genomic, and epigenetic discoveries will enhance the diagnostic capability, and improve the treatment options. During the preceding 20 years, the identification of polymorphisms and the elucidation of their role in arterial and venous thromboses became an important area of research. Today, a large body of data is available regarding associations of single nucleotide polymorphisms (SNPs) in candidate genes with plasma concentrations and e. g. the risk of ischaemic stroke or myocardial infarction. However, the results for individual polymorphisms and genes are often controversial. It is now well established that besides acquired also hereditary risk factors influence the occurrence of thrombotic events, and environmental factors may add to this risk. Currently available statistical methods are only able to identify combined risk genotypes if very large patient collectives (>10,000 cases) are tested, and appropriate algorithms to evaluate the data have yet to be developed. Further research is needed to understand the functional effects of genetic variants in genes of blood coagulation proteins that are critical to the pathogenesis of arterial and venous thrombotic disorders. In this review genetic variants in selected genes of the haemostatic system and their relevance for arterial and venous thrombosis will be discussed.

The association between gene polymorphisms and leukocytosis with thrombotic complications in patients with essential thrombocythemia and polycythemia vera

Objective: Vascular events are a common complication in patients with polycythemia vera (PV) and essential thrombocythemia (ET). This study aimed to analyze the association between PAI-1 4G/5G and ACE I/D gene polymorphisms, and leukocytosis with thrombosis in patients with PV and ET.

Material and Methods: In total, 64 patients with ET and PV were evaluated. Arterial or venous thrombosis, such as cerebral transient ischemic attack, ischemic stroke, myocardial infarction, peripheral arterial thrombosis, deep venous thrombosis, and pulmonary embolism, were defined as a vascular event. DNA samples were screened for mutations via reverse hybridization strip assay.

Results: In terms of PAI-1 gene polymorphism, the frequency of the 4G and 5G allele was 48.5% and 51.5%, respectively. The ACE allele frequency was 51.2% and 48.8% for D and I, respectively. There wasn’t an association between occurrence of vascular events and the frequency of any allele. In terms of occurrence of vascular events, there weren’t any significance differences between the patients that were carrying the ACE D/D homozygous allele to ACE I/D and those that carried the I/I allele (P = 0.93). There wasn’t a significant difference in occurrence of vascular events between the PAI-1 5G/5G homozygote allele carriers, and the 4G/5G and 4G/4G allele carriers (P = 0.97). Vascular events were significantly more common in the patients with leukocytosis (leukocyte count >10 × 109 L–1) than in those without leukocytosis (leukocyte count ≤10 × 109 L–1) (P = 0.00). Age >60 years was also a significant risk factor for occurrence of vascular events(P = 0.008).

Conclusion: PAI-1 and ACE gene polymorphisms were not considered new risk factors for thrombosis in PV and ET patients. On the other hand, leukocytosis at diagnosis was associated with the occurrence of vascular events in the patients with ET and PV.

Association of genetic variants of fibrinolytic system with stroke and stroke subtypes

Genetic variants of tPA (PLAT) and PAI-1 genes have been suggested to be the risk factors for stroke. In the present case-control study we investigated the association of -7351C/T polymorphism (rs2020918) and I/D polymorphism of tPA gene and Insertion/deletion polymorphism (4G/5G) of PAI-1 gene with genetic predisposition to ischemic stroke. 516 stroke patients and 513, sex and age matched healthy controls were involved in the study. We did not find a significant association of tPA -7351C/T polymorphism and PAI-1 4G/5G polymorphism with stroke. However, in case of I/D polymorphism significant difference was observed in the genotypic distribution and allelic frequency between the stroke patients and healthy controls. DD genotype and D allele associated significantly with stroke (p=0.002 and <0.001 respectively). We also found significant association of I/D polymorphism with intracranial large artery atherosclerosis and stroke of undetermined etiology. Exploring the association between gene-gene interaction (26 combinations including the three variants) and stroke, we found that individuals with CC+4G4G+DD, CC+5G5G+ID, CT+4G5G+ID, CT+5G5G+II, CT+5G5G+ID and TT+4G5G+II had a significantly higher risk of stroke. The results of this study suggest that -7351C/T polymorphism of tPA and 4G/5G polymorphism of PAI-1 are not associated with stroke, while as DD genotype and D allele of tPA gene are important risk factors for ischemic stroke. Further we found that the subjects with different tPA and PAI genotype combinations displayed a significantly high risk for overall ischemic stroke suggesting that gene-gene interaction involving more variants may change the susceptibility of particular subjects to the disease.

Successful intravenous thrombolysis in a 14-year-old boy with ischemic stroke

We report a healthy 14-year-old boy with an acute left middle cerebral artery stroke, treated 2 hours after the onset of symptoms with intravenous recombinant tissue plasminogen activator (r-TPA). Recanalization of the middle cerebral artery was documented with transcranial Doppler during the first 5 minutes of intravenous r-TPA perfusion, and progressive recovery of the neurological deficits occurred. Although lack of evidence regarding safety and efficacy in children precludes the recommendation of systematic use of r-TPA in pediatric stroke, we propose that this option should be considered and discussed with the parents, especially in older children presenting within 3 hours in centers with experience in adult thrombolysis.

Prevalence of the fibrinogen beta-chain, angiotensin-converting enzyme and plasminogen activator inhibitor-1 polymorphisms in Costa Rican young adults with thrombotic disease

Thrombotic disease is a multifactorial condition that involves both classical and genetic risk factors. We studied the association between the classical risk factors of hypertension and smoking, and polymorphisms on the genes of the angiotensin-converting enzyme (ACE), the beta-chain of fibrinogen (FG), and the plasminogen activator inhibitor-1 (PAI-1) in patients with venous and arterial thrombosis. The present investigation is a retrospective case-control study. A total of 340 participants were analyzed, including 162 patients and 178 healthy controls. Hypertension and smoking showed a significant association with thrombotic disease (p < 0.05) but FG level was found significant risk factor only for the venous thrombosis (VT) group (p < 0.04). Significant differences between thrombotic groups were found for the studied polymorphisms of PAI-1 (p < 0.0014), but for both FG beta-chain gene polymorphisms, none of the molecular analyses showed a positive sample for any mutating allele (p > 0.05). For the ACE polymorphism, the I allele present a protective effect in the general thrombotic group. This is one of the first reports in a Latin-American population dealing with these molecular markers and thrombotic diseases.

A-G-4G haplotype of PAI-1 gene polymorphisms -844 G/A, HindIII G/C, and -675 4G/5G is associated with increased risk of ischemic stroke caused by small vessel disease

BACKGROUND

Plasminogen activator inhibitor type 1 (PAI-1) is the major inhibitor of fibrinolysis. It was reported that PAI-1 gene polymorphisms affected PAI-1 level and might therefore influence the risk of vascular diseases, including stroke. We studied the association of three common polymorphisms in PAI-1 gene (-844 G/A, -675 4G/5G, and HindIII G/C) with the odds of different causes of ischemic stroke.

METHODS

We studied 390 patients with ischemic stroke due to large vessel disease (n = 117), small vessel disease (n = 121), and cardioembolism (n = 152) as well as 291 controls. The etiology of ischemic stroke was established using TOAST criteria. PAI-1 polymorphisms were genotyped with restriction fragment length polymorphism and single strand conformation polymorphism method.

RESULTS

A-G-4G haplotype of PAI-1 gene was found more frequently in stroke patients with small vessel disease than in control subjects (44.9% vs 35.7%; P = 0.02). No association was found between investigated genotype or allele frequencies and distinct causes of ischemic stroke.

CONCLUSIONS

Our results demonstrate that A-G-4G PAI-1 gene haplotype is associated with increased risk of small vessel disease stroke, but this study does not support an association of -844 G/A, -675 4G/5G, and HindIII G/C PAI-1 gene polymorphisms with particular etiology of ischemic stroke.

Plasminogen activator inhibitor-1 4G/5G polymorphism and risk of ischemic stroke: a meta-analysis

This study investigated the hypothesis that the insertion/deletion (4G/5G) polymorphism of the plasminogen activator inhibitor type-1 gene affects the risk for ischemic stroke, since results concerning this association have been controversial. We therefore performed a meta-analysis of published data regarding this issue. A comprehensive electronic search was carried out until January 2006. The analysis was performed using random-effects models and meta-regression. Eighteen eligible studies were retrieved (15 case-control studies and three cohort studies). The case-control studies included 3104 cases and 4870 control individuals concerning the contrast of 4G/4G versus remaining genotypes. The 4G pooled allele frequencies in cases and controls were 54.21 and 54.75%, respectively. Overall, the per-allele odds ratio of the 4G allele was 0.98 (95% confidence interval, 0.858-1.121). Regarding genotypes, we derived nonsignificant odds ratios in all contrasts. The subanalysis including the three studies with a prospective design in the 4G/4G versus 5G/5G contrast derived a significant result (relative risk, 0.523; 95% confidence interval, 0.353-0.775), but the estimated effect size was insignificant when cohort and case-control studies were analyzed together (relative risk, 0.848; 95% confidence interval, 0.662-1.087). We failed to demonstrate a significant association between the 4G/5G polymorphism and ischemic stroke under basal conditions. Determination of plasminogen activator inhibitor type-1 function seems of much higher clinical value than determination of the 4G/5G polymorphism. The effect of this genotype on risk of ischemic stroke in acute stressful diseases and the role of cohort studies in genetic epidemiology, however, warrant further investigation.

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 PAI-1 4G/5G and -844G/A Gene Polymorphism and Changes in PAI-1/tPA Levels in Stroke: A Case-Control Study

Mutations in the plasminogen activator inhibitor-1 (PAI-1) gene, along with altered PAI-1 and tissue-type plasminogen activator (tPA) levels, have been implicated in stroke pathogenesis. We investigated the association of PAI-1 and tPA levels with stroke as a function of PAI-1 4G/5G and -844G/A genotypes, as well as the link between these PAI-1 gene variants and stroke risk, in a case-control study of 135 ischemic stroke patient, diagnosed according to clinical and radiologic findings and confirmed by computed tomography scan. Controls (n = 118) were age- and sex-matched and had no personal/family history of stroke. PAI-1 4G/5G and -844G/A genotyping were done by polymerase chain reaction-restriction fragment length polymorphism, and PAI-1 and tPA levels were measured by enzyme immunoassay. Significant elevation in PAI-1 and marked reduction in tPA levels were seen in stroke patients and were correlated with 4G/5G, but not with -844G/A, PAI-1 variants. Whereas the frequencies of 4G or -844A alleles were comparable between patients and controls, 4G/4G carriers had reduced risk of stroke compared with other genotypes (odds ratio [OR] = 0.54; 95% confidence interval [CI] = 0.31-0.95). The 4G/-844A haplotype also was more closely associated with reduced stroke risk (OR = 0.43; 95% CI = 0.20-0.97) than 5G/-844A or 4G/-844G haplotypes. Regression analysis demonstrated that 4G homozygosity (OR = 0.176), hypertension (OR = 6.288), and body mass index (OR = 1.325) were independent predictors of stroke. The protective effect of 4G allele against stroke suggests involvement of PAI-1 4G/5G polymorphism in stroke through a mechanism not related to fibrinolysis, possibly involving altered plaque stabilization, and/or through antagonism of tPA effects.

Plasminogen Activator Inhibitor-1 (PAI-1) gene 4G/5G alleles frequency distribution in the Lebanese population

Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis. Increased plasma PAI-1 levels play an essential role in the pathogenesis of cardiovascular risk and other diseases associated with thrombosis. The 4G/5G polymorphism of the PAI-1 promoter region has been extensively studied in different populations. We studied 160 healthy unrelated Lebanese individuals using a reverse hybridization PCR assay to detect the 5G/5G, 4G/5G and, 4G/4G genotypes of the PAI-1 gene and the frequencies of the 4G and 5G alleles. We found that 4G/5G genotype was the most prevalent (45.6%) followed by 5G/5G (36.9%) and 4G/4G (17.5%). The frequencies of the 4G and 5G alleles were calculated to be 0.403 and 0.597, respectively. Compared to other ethnic communities, the Lebanese population was found to harbour a relatively high prevalence of the rare 4G allele. This, in turn, may predispose this population to develop cardiovascular diseases and other thrombotic clinical conditions. This study aids to enhance our understanding of the genetic features of the Lebanese population.

Plasminogen activator inhibitor type 1 gene polymorphisms and haplotypes are associated with plasma plasminogen activator inhibitor type 1 levels but not with myocardial infarction or stroke

BACKGROUND

The 4G allele in the promoter region of the plasminogen activator inhibitor type 1 (PAI-1) gene is associated with higher plasma PAI-1 levels and activity, but its association with cardiovascular diseases is unclear. We investigated the association of polymorphisms and common haplotypes of the PAI-1 gene with plasma PAI-1 levels, as well as the risk of myocardial infarction and stroke.

METHODS AND RESULTS

This study is a prospective analysis of 2995 community-based participants (41% blacks and 51% women) aged 70 to 79 years old in the Health, Aging, and Body Composition Study. From 1997/1998 to 2001, 177 myocardial infarction events and 101 stroke events were identified. In addition to the 4G/5G polymorphism, 2 potential functional variants and other 4 haplotype-tagging variants were genotyped. In general linear models, the 4G allele was associated with higher PAI-1 levels after adjusting for age, sex, race, and site (26, 29, and 32 ng/mL for 5G/5G, 4G/5G, and 4G/4G, respectively; P for trend < .0001), but none of the other 6 polymorphisms was associated with PAI-1 levels. Haplotype analysis produced similar results. However, in Cox proportional hazard models, neither the polymorphisms nor the common haplotypes of the PAI-1 gene was associated with the risk of either myocardial infarction or stroke.

CONCLUSIONS

The 4G allele is associated with higher PAI-1 levels, but this study does not support an association of the PAI gene polymorphisms with the risk of either myocardial infarction or stroke.

Fibrinolytic Gene Polymorphism and Ischemic Stroke

Background and Purpose— The tissue-type plasminogen activator (tPA) −7351C>T and the plasminogen activator inhibitor type 1 (PAI-1) -675 4G >5G polymorphisms influence transcriptional activity. Both variants have been associated with myocardial infarction, with increased risk for the T and 4G allele, respectively. In this study we investigated the possible association between these polymorphisms, the respective plasma protein levels, and ischemic stroke.

Methods— In the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), 600 patients with acute ischemic stroke aged 18 to 69 years and 600 matched community controls were recruited. Stroke subtype was determined using Trial of Org 10172 in Acute Treatment criteria.

Results— There were no associations between individual genetic variants and ischemic stroke. The multivariate-adjusted odds ratio for overall ischemic stroke was 1.11 (95% CI 0.87 to 1.43) for tPA T allele carriers, and 0.84 (95% CI, 0.64 to 1.11) for subjects homozygous for the PAI-1 4G allele. When genotypes were combined, a protective effect for the tPA CC/PAI-1 4G4G genotype combination was observed (odds ratio 0.65, 95% CI 0.43 to 0.98; P <0.05). Plasma levels of tPA and PAI-1 antigen at follow-up were independently associated with overall ischemic stroke. tPA-antigen differed by stroke subtype and was highest among those with large-vessel disease and cardioembolic stroke.

Conclusions— Neither the tPA −7351C>T nor the PAI-1 to 675 4G >5G polymorphism showed significant association with ischemic stroke. For the tPA CC/PAI-1 4G4G genotype combination, a protective effect was observed. Collectively, these results are consistent with a more complex role for tPA and PAI-1 in the brain as compared with the heart.

A polymorphism of the plasminogen activator inhibitor-1 gene promoter and the polycystic ovary syndrome

OBJECTIVE

To investigate the association of a common 5G/4G polymorphism of the plasminogen activator inhibitor-1 gene (PAI1) with occurrence and clinical characteristics of the polycystic ovary syndrome (PCOS).

STUDY DESIGN

In a case-control study, we evaluated a series of 106 Caucasian women with PCOS and 102 healthy controls. Women completed a detailed questionnaire and underwent a peripheral venous puncture, ultrasonography, and a standardized oral glucose tolerance test (OGTT). The PAI1 gene promoter polymorphism was evaluated using PCR.

RESULTS

Allele and genotype frequencies were not significantly different among women with PCOS and controls (P=0.3 and 0.6, respectively). In women with PCOS, presence of the 5G/4G polymorphism of PAI1 was not associated with changes in serum hormone levels or with clinical characteristics.

CONCLUSIONS

The 5G/4G polymorphism of the PAI1 promoter is not associated with occurrence and phenotype of the PCOS.

Plasminogen Activator Inhibitor-1 4G/5G Polymorphism and Risk of Stroke

Background and Purpose— Impaired fibrinolytic function secondary to elevated plasminogen activator inhibitor-1 (PAI-1) levels has been implicated in ischemic stroke. PAI-1 levels are determined by genetic factors and environmental factors, triglyceride levels in particular. The aim of this study was to investigate the common functional 4/5 guanosine (4G/5G) polymorphism in the promoter region of the PAI-1 gene and the risk of stroke.

Methods— A nested case–control study design was applied, using baseline data for 2 independent cohorts obtained at population-based surveys in northern Sweden. In study A, there were 113, and in study B, there were 275 individuals without major concomitant disease at baseline who later experienced a first-ever stroke. Blood samples obtained at baseline were analyzed for potential risk factors, including the 4G/5G polymorphism of the PAI-1 gene.

Results— The 4G allele of the PAI-1 polymorphism was associated with an increased risk of future ischemic stroke in both studies (odds ratio [OR] of 4G homozygosity, 1.87; 95% CI, 1.12 to 3.15 in study A; OR of 4G homozygosity, 1.56; 95% CI, 1.12 to 2.16 in study B). Individuals with the combination of hypertriglyceridemia and 4G homozygosity were at the greatest risk of developing stroke. Multiple logistic regression analysis identified 4G homozygosity, systolic blood pressure, and diabetes as independent predictors of ischemic stroke.

Conclusions— Identical findings in 2 independent studies strongly suggest a true and clinically important association between PAI-1 4G/5G genotype and risk of future ischemic stroke. The observed modification of the genotype effect by triglycerides may be interpreted as a gene–environment interaction.

Distribution of PAI-1 promoter 4G/5G polymorphism in healthy Chinese and functional characterization using a luciferase reporter vector

The aim of this study was to analyze the distribution of plasminogen activator inhibitor-1 (PAI-1) promoter 4G/5G polymorphism in healthy Chinese and compare the transcription activity of the two PAI-1 promoters using luciferase reporter vector pGL(3). PAI-1 promoter 4G/5G polymorphism was analyzed in 77 healthy Chinese using allele-specific polymerase chain reaction (PCR). The PAI-1 promoters from individuals homozygous for the insertion (5G) and deletion (4G) were cloned into luciferase reporter vector pGL(3), respectively. The transcription activities of the two promoters (PAI-1-4G and PAI-1-5G) were then compared using the luciferase reporter vectors expressed in ECV304 and HepG(2) cell lines. Among the 77 healthy Chinese the genotype frequency for 4G/4G, 4G/5G, and 5G/5G was 49.1, 44.1, and 6.5%, respectively. Both of the two PAI-1 promoters cloned into luciferase reporter vector pGL(3), expressed very well both in ECV304 and HepG(2), and have similar basic transcription activity. Thrombin (10-20 U/ml) has no effects on the transcription activity of the two promoters expressed in ECV304, while in the HepG(2) cell line interleukin-1 (IL-1) 158 U/ml increased the transcription activity of PAI-1-4G by 67% (p<0.05, n=5) without effects on PAI-1-5G transcription activity. The distribution of PAI-1 promoter 4G/5G polymorphism in Chinese is obviously different from that in Caucasians with the 4G allele more frequently found in Chinese. PAI-1 promoter 4G/5G polymorphism does not alter basic transcription activity and 4G promoter has increased response to IL-1.

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

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

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

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

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

Prothrombotic gene polymorphisms and atherothrombotic cerebral infarction

OBJECTIVES

To test the hypothesis whether risk genotypes of the prothrombotic gene polymorphisms (I/D 4G5G PAI-1, G1691A factor V point mutation, factor VII Arg/Gln353) are risk factors for ACI in the Slovene population. The study sought an association between the insertion/deletion 4G/5G-plasminogen activator inhibitor 1 (PAI-1) gene polymorphism, the 1691G-A factor V point mutation or the arg353-to-gln factor VII gene polymorphism and atherothrombotic cerebral infarction (ACI).

MATERIAL AND METHODS

Ninety-six Slovene patients who suffered ACI were compared with 115 control subjects clinically free of cerebrovascular disease. Insertion/deletion 4G/5G PAI-1 gene polymorphism, 1691G-A factor V point mutation and arg353-to-gln polymorphism in the factor VII were determined using polymerase chain reaction.

RESULTS

The 4G4G genotype of 4G5G PAI-1 gene polymorphism was less frequent in cases (21.9%) than in controls (35.6%; OR = 0.5, 95% CI = 0.3-1; P = 0.033). No association was found either between the factor V point mutation (1691G-A) or the RR genotype of the factor VII Arg/Gln353 gene polymorphism and the risk of ACI using univariate analysis.

CONCLUSION

The 4G/4G-PAI-1 genotype might be a protective factor against ACI, whereas the factor V point mutation (1691G-A) and the factor VII Arg/Gln353 gene polymorphism have not proved to be risk factors for ACI.

4G/5G promoter polymorphism of plasminogen activator inhibitor-1, lipid profiles, and ischemic stroke

The 4G allele of common 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene is associated with increased PAI-1 transcription and has been proposed as a candidate genetic risk factor for thrombotic diseases. We investigated the relationship between this polymorphism and lipid profiles and stroke risk. One hundred patients with ischemic stroke and 150 age- and sex-matched control subjects were enrolled. PAI-1 genotype was determined with the use of polymerase chain reaction and restriction-length analysis. Genotype distribution in the stroke group was 40% 4G/4G, 46% 4G/5G, and 14% 5G/5G; in the control group it was 38.7% 4G/4G, 45.3% 4G/5G, and 16% 5G/5G. The allele and genotype frequencies of 4G/5G polymorphism were not different between the stroke and control groups. Control subjects who were homozygous for the 4G allele had significantly lower high-density lipoprotein (HDL) cholesterol levels than did those carrying the 5G allele (51.2 +/- 11.8 vs 58.4 +/- 15.8 mg/dL; P =.002). In the control group, regression analysis revealed a significant contribution of 4G/4G genotype to increased triglyceride (P =.042) and to decreased HDL cholesterol (P <.001) levels. Our findings suggest that PAI-1 4G/5G promoter polymorphism alone is not associated with ischemic stroke. However, this polymorphism influences lipid levels, and the underlying mechanism must be determined.

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.

Cryptogenic stroke in relation to genetic variation in clotting factors and other genetic polymorphisms among young men and women

BACKGROUND AND PURPOSE

The purpose of the present study was to compare the prevalences of genetic polymorphisms in persons with cryptogenic stroke with those among stroke patients with evidence of large-artery occlusive disease or an unequivocal cardioembolic source (noncryptogenic stroke).

METHODS

We compared the prevalences of genetic polymorphisms thought to be related to thrombi formation in young stroke patients with evidence of large-artery occlusive disease or an unequivocal cardioembolic source (noncryptogenic stroke; controls; n=79) with those in young stroke patients without such sources (cryptogenic stroke; cases; n=67). Common variations in the genes encoding factor V, prothrombin, angiotensin I-converting enzyme, 5,10-methylenetetrahydrofolate reductase, endothelial cell nitric oxide synthase, tissue plasminogen activator, plasminogen activator inhibitor-1, and fibrinogen were evaluated. We also compared the allele prevalence of these genes among all stroke patients with those among a large pool of historical controls assayed for these genes.

RESULTS

None of these genetic polymorphisms was statistically significantly related to cryptogenic stroke. With respect to a comparison of all ischemic stroke with historical controls, only the prevalence of tissue plasminogen activator D allele among stroke subjects was statistically significantly higher than that of the historical controls (P=0.0014).

CONCLUSIONS

These findings generally do not support the hypothesis that genes associated with a prothrombotic state are risk factors among a subgroup of young people with stroke of undetermined cause. Except for the D tissue plasminogen activator allele, the findings also indicated that these genetic factors are unrelated, or only weakly related, to all ischemic stroke.

The plasminogen activator inhibitor (PAI)-1 promoter 4G/4G genotype is not associated with ischemic stroke in a population of German children. Childhood Stroke Study Group

OBJECTIVES

To investigate the relationship between an insertion/deletion (4G/5G) polymorphism of the plasminogen activator inhibitor (PAI)-1 gene and childhood patients with a past history of ischemic stroke.

METHODS

The PAI-1 4G/4G genotype and the coinheritance with lipoprotein (Lp) (a) levels, the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, and the methylene-tetrahydrofolate reductase (MTHFR) T677T genotype were studied in 198 Caucasian children with stroke and 951 controls (same age, sex and ethnical distribution). In a randomly selected subgroup of patients/controls (n=60) PAI-I activities have been investigated.

RESULTS

The distribution of the 4G/5G genotypes was no different in childhood stroke patients and controls, with a 4G allele frequency of 55.8% in patients compared with 53.8% in control subjects (P=0.49). The 4G/4G genotype compared with the remaining genotypes was present in 43 cases and 167 (17.6% vs. 21.7%; OR/CI: 1.30/0.89-1.98; P=0.3). PAI-1 activity was significantly elevated (P < 0.001) in the patient group.

CONCLUSIONS

Data presented here suggest that the 4G/4G genotype is not a major risk factor in the aetiology of childhood ischemic stroke.