The influence of age and smoking on hemostatic parameters in the chinese people

PAI-1 gain-of-function genotype, factors increasing PAI-1 levels, and airway obstruction: The GALA II Cohort

BACKGROUND

PAI-1 gain-of-function variants promote airway fibrosis and are associated with asthma and with worse lung function in subjects with asthma.

OBJECTIVE

We sought to determine whether the association of a gain-of-function polymorphism in plasminogen activator inhibitor-1 (PAI-1) with airway obstruction is modified by asthma status, and whether any genotype effect persists after accounting for common exposures that increase PAI-1 level.

METHODS

We studied 2070 Latino children (8-21y) with genotypic and pulmonary function data from the GALA II cohort. We estimated the relationship of the PAI-1 risk allele with FEV1/FVC by multivariate linear regression, stratified by asthma status. We examined the association of the polymorphism with asthma and airway obstruction within asthmatics via multivariate logistic regression. We replicated associations in the SAPPHIRE cohort of African Americans (n=1056). Secondary analysis included the effect of the at-risk polymorphism on postbronchodilator lung function.

RESULTS

There was an interaction between asthma status and the PAI-1 polymorphism on FEV₁ /FVC (P=.03). The gain-of-function variants, genotypes (AA/AG), were associated with lower FEV₁ /FVC in subjects with asthma (β=-1.25, CI: -2.14,-0.35, P=.006), but not in controls. Subjects with asthma and the AA/AG genotypes had a 5% decrease in FEV₁ /FVC (P<.001). In asthmatics, the risk genotype (AA/AG) was associated with a 39% increase in risk of clinically relevant airway obstruction (OR=1.39, CI: 1.01, 1.92, P=.04). These associations persisted after exclusion of factors that increase PAI-1 including tobacco exposure and obesity.

CONCLUSIONS AND CLINICAL RELEVANCE

The decrease in the FEV₁ /FVC ratio associated with the risk genotype was modified by asthma status. The genotype increased the odds of airway obstruction by 75% within asthmatics only. As exposures known to increase PAI-1 levels did not mitigate this association, PAI-1 may contribute to airway obstruction in the context of chronic asthmatic airway inflammation.

Plasminogen activator inhibitor-1 (PAI-1): a key factor linking fibrinolysis and age-related subclinical and clinical conditions

INTRODUCTION

The close relationship existing between aging and thrombosis has growingly been studied in this last decade. The age-related development of a prothrombotic imbalance in the fibrinolysis homeostasis has been hypothesized as the basis of this increased cardiovascular and cerebrovascular risk. Fibrinolysis is the result of the interactions among multiple plasminogen activators and inhibitors constituting the enzymatic cascade, and ultimately leading to the degradation of fibrin. The plasminogen activator system plays a key role in a wide range of physiological and pathological processes.

METHODS

Narrative review.

RESULTS

Plasminogen activator inhibitor-1 (PAI-1) is a member of the superfamily of serine-protease inhibitors (or serpins), and the principal inhibitor of both the tissue-type and the urokinase-type plasminogen activator, the two plasminogen activators able to activate plasminogen. Current evidence describing the central role played by PAI-1 in a number of age-related subclinical (i.e., inflammation, atherosclerosis, insulin resistance) and clinical (i.e., obesity, comorbidities, Werner syndrome) conditions is presented.

CONCLUSIONS

Despite some controversial and unclear issues, PAI-1 represents an extremely promising marker that may become a biological parameter to be progressively considered in the prognostic evaluation, in the disease monitoring, and as treatment target of age-related conditions in the future.

Hemostatic risk factors of coronary artery disease in the Chinese

In order to find out the hemostatic risk factors of coronary artery disease in the Chinese, antithrombin III concentration, factor VII and fibrinogen assays, plasminogen activator inhibitor-1 antigen and platelet count were determined in 51 healthy controls (mean age 63.5 years, S.D. 10.3), 55 diabetics (mean age 66.0 years, S.D. 4.8) and 56 patients with arteriographically proved coronary artery disease (mean age 63.8 years, S.D. 8.7). Of the coronary artery disease group, 19 had single vessel disease, 21 had double vessel disease and 16 had triple vessel disease. Sixteen of this group also had a past history of myocardial infarction. There was no significant difference of the hemostasis parameters between diabetics and controls. Fibrinogen and factor VII, but not plasminogen activator inhibitor, were significantly higher in coronary artery disease patients than in controls (P = 0.0001, both) and in diabetics (P = 0.0001, both). No significant difference in the parameters was found in the coronary artery disease group, whether the patients had single vessel disease, double vessel disease, or triple vessel disease, or were with or without past myocardial infarction. In the myocardial infarction group, fibrinogen and factor VII were significantly higher than in the controls (P < 0.00005 and 0.0001, respectively) and in the diabetics (P = 0.0002 and 0.0004, respectively). We suggest that increased levels of fibrinogen and factor VII, but not plasminogen activator inhibitor, would be the hemostatic risk factors of coronary artery disease in the Chinese.