Is the plasminogen activator inhibitor-1 gene a candidate gene predisposing to hypertension? Results from a population-based study in Spain

Plasminogen activator inhibitor-1 activity and the 4G/5G polymorphism are prospectively associated with blood pressure and hypertension status

OBJECTIVES

Plasminogen activator inhibitor-1 (PAI-1) has consistently shown positive associations with blood pressure (BP). Whether elevations in PAI-1 levels precede or result from raised BP is still under debate and data on prospective studies are limited. Hence, we investigated the prospective associations of PAI-1 and the 4G/5G polymorphism with brachial and central BP and pulse pressure (PP) over a 10-year period.

METHODS

Black South Africans aged 30 years and older were included. Baseline data collection commenced in 2005 (n = 2010) with follow-up data collection in 2010 (n = 1288) and 2015 (n = 926). Plasma PAI-1 activity (PAI-1act), 4G/5G polymorphism genotyping, waist circumference and BP measurements were performed and analysed using sequential regression and mixed models.

RESULTS

In multivariable adjusted analyses, PAI-1act and the 4G/4G (vs. the 5G/5G) genotype increased the odds of developing hypertension in the total group [1.04 (1.01; 1.08) and 1.82 (1.07; 3.12) respectively]. Furthermore, PAI-1act was prospectively associated with brachial SBP (r = 0.0815) and PP (r = 0.0832) in the total group, and with central PP in women (r = 0.1125; all P < 0.05). Addition of waist circumference to the models either decreased or nullified the contribution of PAI-1act to BP and hypertension development.

CONCLUSION

PAI-1act and the 4G/4G (vs. the 5G/5G) genotype increased the odds of developing hypertension. Furthermore, PAI-1act associated prospectively with both brachial and central BP. These associations were mediated in part by central adiposity. The study supports the hypothesis that PAI-1 also contributes to hypertension development rather than solely being a consequence thereof.

Association between the rs6950982 polymorphism near the SERPINE1 gene and blood pressure and lipid parameters in a high-cardiovascular-risk population: interaction with Mediterranean diet

The SERPINE1 (serpin peptidase inhibitor, clade E, member 1) gene, better known by its previous symbol PAI-1 (plasminogen activator inhibitor 1), has been associated with cardiovascular phenotypes with differing results. Our aim was to examine the association between the rs6950982 (G > A) near the SERPINE1 gene, blood pressure (BP) and plasma lipid concentrations as well as the modulation of the polymorphism effects by adherence to Mediterranean diet (AMD). We studied 945 high-cardiovascular-risk subjects. Biochemical, clinical, dietary and genetic data (rs6950982) were obtained. We also determined the common rs1799768 (4G/5G), for checking independent effects. AMD was measured by a validated questionnaire, and four groups were considered. rs6950982 (A > G) and rs1799768 (4G/5G) were only in moderate-low linkage disequilibrium (D' = 0.719; r (2) = 0.167). The most significant associations we obtained were with rs6950982 (A > G). In males, the G allele was nominally associated with higher diastolic BP (AA: 81.5 ± 10.9, AG: 82.1 ± 11.4, GG: 85.7 ± 10.5 mmHg; P additive = 0.030) and systolic BP (AA + AG: 141.4 ± 6.9 mmHg vs. GG: 149.8 ± 8.0 mmHg; P recessive = 0.036). In the whole population, the rs6950982 was also associated with plasma lipids. Subject with the G allele presented higher total cholesterol (P additive = 0.016, P recessive = 0.011), low-density lipoprotein cholesterol (P additive = 0.032, P recessive = 0.031) and triglycerides (P additive = 0.040, P recessive = 0.029). AMD modulated the effect of rs6950982 on triglyceride concentrations (P for interaction = 0.036). Greater AMD reduced the higher triglyceride concentrations in GG subjects. No significant interactions were found for the other parameters. The rs6950982 was associated with higher BP in men and higher triglycerides in the whole population, this association being modulated by AMD.

Insulin resistance explains the relationship between novel cardiovascular risk factors and hypertension. The Telde Study

BACKGROUND

Most studies describing an association between hypertension and an inflammatory/pro-thrombotic state do not assess insulin resistance.

AIM

To examine the association between hypertension and new cardiovascular risk factors when considering both classical risk factors and insulin resistance.

METHODS

In a population-based sample of 1030 subjects, clinical information and blood samples were obtained. Subjects were classified according to the presence or absence of hypertension, and insulin resistance was estimated using the homeostasis model of assessment (HOMA). To identify variables independently associated with hypertension, a four-model multiple logistic regression was performed: model 1 included novel risk factors (Plasminogen Activator Inhibitor- 1 [PAI-1], fibrinogen, von Willebrand Factor [vWF], lipoprotein(a), homocysteine and C-reactive Protein [CRP]); model 2, novel risk factors plus HOMA; model 3 included both classical (smoking, triglycerides, HDL cholesterol, total cholesterol, waist circumference and diabetes) and novel risk factors and model 4, model 3 plus HOMA. All were adjusted for age, BMI and gender and compared using Akaike's Information Criterion (AIC).

RESULTS

In model 1, only PAI-1, age and BMI showed association with hypertension.When HOMA and classical risk factors were also included, PAI-1 was replaced by triglyceride, smoking and diabetes. The lowest AIC value (best adjustment) was displayed by model 4, comprising all of the variables. Only age, BMI, HOMA and smoking remained significantly associated with hypertension.

CONCLUSIONS

The novel cardiovascular risk factors assessed do not add information as markers of hypertension when classical risk factors or insulin resistance are included in the evaluation.

Gender-specific association of the plasminogen activator inhibitor-1 4G/5G polymorphism with central arterial blood pressure

BACKGROUND

The functional plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism has previously been associated with hypertension. In recent years, central blood pressure, rather than brachial has been argued a better measure of cardiovascular damage and clinical outcome. The aim of this study was to investigate the possible influence of the 4G/5G polymorphism on central arterial blood pressure in a cohort of elderly individuals.

METHODS

We studied 410 individuals, 216 men and 194 women, aged 70-88. Central pressures and pulse waveforms were calculated from the radial artery pressure waveform by the use of the SphygmoCor system and a generalized transfer function. Brachial pressure was recorded using oscillometric technique (Dinamap, Critikon, Tampa, FL). PAI-1 antigen was determined in plasma.

RESULTS

The results showed that central pressures were higher in women carrying the PAI-1 4G/4G genotype compared to female carriers of the 5G/5G genotype, (P = 0.025, P = 0.002, and P = 0.002 for central systolic-, diastolic-, and mean arterial pressure, respectively). The association remained after adjustment for potentially confounding factors related to hypertension. No association of the PAI-1 genotype with blood pressure was found in men. Multiple regression analysis revealed an association between PAI-1 genotype and plasma PAI-1 levels (P = 0.048).

CONCLUSIONS

Our findings show a gender-specific association of the PAI-1 4G/5G polymorphism with central arterial blood pressure. The genotype effect was independent of other risk factors related to hypertension, suggesting that impaired fibrinolytic potential may play an important role in the development of central hypertension in women.

Plasminogen activator inhibitor type-1 gene 4G/5G polymorphism is associated with hypertensive patients in the Turkish population

This study has been performed on hypertensive patients in the Turkish population to determine the frequency of 4G/5G polymorphism genotypes of plasminogen activator inhibitor type-1 gene and with the aim of examining the role of this polymorphism in hypertension development. Genomic DNA obtained from 284 persons (176 patients with hypertension and 108 healthy controls) was used in the study. DNA was multiplied by polymerase chain reaction using 4G and 5G allele-specific primers. Polymerase chain reaction products were assessed by being exposed to 2% agarose gel electrophoresis. Results were evaluated with the chi-square test. The 4G allele frequency was 31.25% and the 5G allele frequency was 68.75% in patients, whereas it was 49/51% in a control group. 5G5G genotype was found statistically high (p < 0.001) in patients relative to controls. This study showed that the plasminogen activator inhibitor type-1 gene 4G/5G polymorphism and the 5G5G genotype appear to be associated with an elevated risk of developing hypertension in a representative sample of Turkish population.

Plasminogen activator inhibitor-1 and asthma: role in the pathogenesis and molecular regulation

Plasminogen activator inhibitor (PAI)-1 is a major inhibitor of the fibrinolytic system. PAI-1 levels are markedly increased in asthmatic airways, and mast cells (MCs), a pivotal cell type in the pathogenesis of asthma, are one of the main sources of PAI-1 production. Recent studies suggest that PAI-1 may promote the development of asthma by regulating airway remodelling, airway hyperresponsiveness (AHR), and allergic inflammation. The single guanosine nucleotide deletion/insertion polymorphism (4G/5G) at -675 bp of the PAI-1 gene is the major genetic determinant of PAI-1 expression. Plasma PAI-1 level is higher in people with the 4G/4G genotype than in those with the 5G/5G genotype. A strong association between the 4G/5G polymorphism and the risk and the severity of asthma has been suggested. Levels of plasma IgE and PAI-1 and severity of AHR are greater in asthmatic patients with the 4G/4G genotype than in those with the 5G/5G genotype. The PAI-1 promoter with the 4G allele renders higher transcription activity than the PAI-1 promoter with the 5G allele in stimulated MCs. The molecular mechanism for the 4G allele-mediated higher PAI-1 expression is associated with greater binding of upstream stimulatory factor-1 to the E-box adjacent to the 4G site (E-4G) than to the E-5G. In summary, PAI-1 may play an important role in the pathogenesis of asthma. Further studies evaluating the mechanisms of PAI-1 action and regulation may lead to the development of a novel prognostic factor and therapeutic target for the treatment and prevention of asthma and other PAI-1-associated diseases.

Genes overexpressed in cerebral arteries following salt-induced hypertensive disease are regulated by angiotensin II, JunB, and CREB

Although changes in gene expression are necessary for arterial remodeling during hypertension, the genes altered and their mechanisms of regulation remain uncertain. The goal of this study was to identify cerebral artery genes altered by hypertension and define signaling pathways important in their regulation. Intact cerebral arteries from Dahl salt-sensitive normotensive and hypertensive high-salt (HS) rats were examined by immunostaining, revealing an increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and expression of the proliferative marker Ki-67 in arteries from hypertensive animals. Arterial RNA analyzed by microarray and validated with RT-quantitative PCR revealed that jun family member junB and matricellular genes plasminogen activator inhibitor-1 (PAI-1) and osteopontin (OPN) were significantly overexpressed in HS arteries. Fisher exact test and annotation-based gene subsets showed that genes upregulated by Jun and Ca2+/cAMP-response element-binding protein (CREB) were overrepresented. A model of cultured rat cerebrovascular smooth muscle cells was used to test the hypothesis that angiotensin II (ANG II), JunB, and CREB are important in the regulation of genes identified in the rat hypertension model. ANG II induced a transient induction of junB and a delayed induction of PAI-1 and OPN mRNA levels, which were reduced by ERK inhibition with U-0126. Silencing junB using small-interfering RNA reduced mRNA levels of OPN but not PAI-1. The silencing of CREB reduced PAI-1 induction by ANG II but enhanced the transcription of OPN. Together, these results suggest that salt-induced hypertensive disease promotes changes in matricellular genes that are stimulated by ANG II, regulated by ERK, and selectively regulated by JunB and CREB.