Plasminogen Activator Inhibitor-1 Antigen Research Articles

A case of deficiency of plasma plasminogen activator inhibitor-1 related to Ala15Thr mutation in its signal peptide

The patient was a 34-year-old man with life-long bleeding episodes, whose hemorrhage problem was characterized predominantly by prolonged bleeding at surgical or traumatic sites. All routine coagulation parameters were within normal ranges. The patient's bleeding tendency was not caused by factor XIII deficiency, alpha2-antiplasmin deficiency, or tissue type-plasminogen activator increase. His characteristic abnormalities of fibrinolysis included shortened euglobulin clot lysis time, low plasminogen activator inhibitor-1 (PAI-1) activity and antigen in plasma, which were remarkably reduced to only about 10% of control. An operation was performed in order to clear two hematomas in the patient's left leg and hip, and subsequent bleeding episodes were well controlled with adjuvant administration of intravenous aminomethylbenoic acid after surgery. PAI-1 gene analysis by polymerase chain reaction product sequencing revealed that the patient had a heterozygous missense mutation G to A transition at nucleotide position 4497 in exon 2, causing replacement of alanine 15 (GCC) to threonine (ACC) at signal peptide. The restriction endonuclease analysis showed that this gene mutation also existed in the patient's father, but not in his mother and 60 normal subjects. The wild-type and mutant plasmids were constructed and transiently transfected into Chinese hamster ovary cell lines; the levels of PAI-1 activity and antigen in the media of the mutant were approximately 70% of the wild type, and the levels of PAI-1 protein in cell lysates were almost equal in wild-type and mutant plasmids. These results indicate that the mutation in signal peptide may partly impair the secretion of PAI-1.

Expressions of urokinase-type plasminogen activator, its receptor and plasminogen activator inhibitor-1 in gastric cancer cells and effects of Helicobacter pylori

ObjectiveDestruction of the extracellular matrix is essential for tumor invasion and metastasis. The relationship between Helicobacter pylori (H. pylori) infection and destruction of the extracellular matrix is not yet clear. Urokinase-type plasminogen activator (uPA) plays an important role in the destruction of the extracellular matrix and basement membrane. Urokinase-type plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1(PAI-1) appear to be associated with these processes. To clarify the role of H. pylori infection in the processes of destruction of the extracellular matrix and basement membrane in cancerous tissue, the effect of H. pylori on the expressions of uPA, uPAR and PAI-1 in cancer cells was investigated.Material and methodsGastric cancer cell lines (MKN45, KATO-III) were co-cultured with H. pylori standard strain (NCTC11637), cagA-negative strain and clinical isolated strain. The specific inductions of uPA, uPAR and PAI-1 mRNA were examined by reverse transcription-polymerase chain reaction (RT-PCR) amplification. The secreted uPA antigen was measured by enzyme-linked immunosorbent assay (ELISA). To evaluate the role of transcription factor NF-κB in uPA and uPAR gene transcription with H. pylori stimulation, the effect of NF-κB inhibitor MG132 on H. pylori-induced uPA and uPAR mRNA expression was examined.ResultsThe expressions of both uPA and uPAR mRNAs in the gastric cancer cell lines (MKN45 and KATO- III) were increased markedly (uPA mRNA; MKN45: 12-fold, KATO-III: 5-fold) (uPAR mRNA; MKN45: 3-fold, KATO-III: 3-fold) with H. pylori NCTC11637 strain stimulation, whereas the expression levels of uPA and uPAR mRNA did not increase with cagA-negative strain stimulation. These cancer cell lines slightly secreted uPA antigen into the culture medium, and the amount of uPA antigen increased dramatically by stimulation with H. pylori NCTC11637 and cagA-positive clinical isolated strains. These gastric cancer cell lines also slightly secreted PAI-1 antigen into the culture medium, and the amount of PAI-1 antigen was not affected by H. pylori NCTC11637 stimulation. H. pylori-induced uPA and uPAR mRNA expressions were strongly down-regulated by pretreatment with MG132 in both cell lines.ConclusionsThe results of this study indicated the possibility that cagA-positive H. pylori may play an important role not only in tissue remodeling, angiogenesis and wound healing but also in the process of degradation of the extracellular matrix breakdown, tumor invasion and metastasis by inducing uPA and uPAR complex in the gastric cancer cells.

The effects of short-term raloxifene therapy on fibrinolysis markers: TAFI, tPA, and PAI-1

Background. Markers of fibrinolysis, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) levels were studied for the evaluation of short-term effects of raloxifene administration in postmenopausal women. Methods. Thirty-nine postmenopausal women with osteopenia or osteoporosis were included in this prospective, controlled clinical study. Twenty-five women were given raloxifene hydrochloride (60 mg/day) plus calcium (500 mg/day). Age-matched controls (n = 14) were given only calcium. Plasma TAFI, tPA, and PAI-1 antigen levels were measured at baseline and after 3 months of treatment by commercially available ELISA kits. Variations of individuals were assessed by Wilcoxon's test. Relationship between those markers and demographic characteristics were investigated. Results. Three months of raloxifene treatment was associated with a significant decrease in the plasma TAFI antigen concentrations (16% change, P < 0.01), and a significant increase in tPA antigen concentrations (25% change, P < 0·05). A significant correlation was found between baseline TAFI antigen concentrations and the duration of amenorrhea (P < 0·05; r = 0·33). Conclusion. We suggest that the increased risk of venous thromboembolism due to raloxifene treatment may be related to increased tPA levels, but not TAFI levels.

Resolution of Budd???Chiari syndrome due to activation of endogenous fibrinolysis that may be induced by weight reduction

We describe a 45-year-old female with polycythemia vera and Leiden factor V mutation, who suffered the subacute form of Budd-Chiari syndrome and was treated with anticoagulants and diuretics. Surprisingly, after 3 months clinical signs of Budd-Chiari syndrome resolved; venography disclosed the resolution of thrombosis in the vena cava inferior and hepatic veins. This was associated with considerable increase of endogenous fibrinolytic activity, documented by a substantial change in the euglobulin clot lysis time, and a decrease of plasminogen activator inhibitor antigen and activity. During the disease the patient followed a diet and significantly reduced her body weight. Putting all data together it could be speculated that weight reduction (along with anticoagulants) considerably activated endogenous fibrinolysis, resulting in spontaneous resolution of Budd-Chiari syndrome. The validity of this explanation should be explored in a larger clinical study.

Relationship of physical fitness, hormone replacement therapy, and hemostatic risk factors in postmenopausal women

This cross-sectional study evaluated the relationship of physical fitness, hormone replacement therapy (HRT), and hemostatic profiles at rest and after an acute bout of maximal exercise in 48 healthy postmenopausal women. Subjects were categorized by fitness and HRT user status into four groups: unfit nonusers, fit nonusers, unfit users, and fit users. Fibrinolytic variables tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) activity, and antigen and prothrombin fragment 1 + 2, a molecular marker of in vivo thrombin generation, were measured before and after maximal exercise. Fibrinogen was also measured at rest. Higher tPA and lower PAI-1 activities (P <0.05) were seen in HRT users and fit groups. tPA and PAI-1 antigens were lower in HRT and fit groups (P <0.05) but not after correction for body mass index. Prothrombin fragment 1 + 2 was lower in the fit groups regardless of HRT status (P <0.05). Fibrinogen was similar in all groups. Favorable hemostatic profiles were observed in physically fit compared with unfit women, especially in HRT nonusers. Thus fitness is more strongly related to these hemostatic risk factors compared with HRT since HRT did not affect these hemostatic variables in fit postmenopausal women.

Elevated sEPCR and PAI-1 Levels, but Not sThrombomodulin Levels in Normal Pregnancy.

Pregnancy is a prothrombotic state. The protein C system is felt to be the major regulatory mechanism for the control of thrombin formation in pregnancy. The protein C (PC) system consists of PC, protein S (PS), thrombomodulin (TM) and endothelial protein C receptor (EPCR). The other component for the control of thrombosis is the fibrinolytic system. Plasminogen activator inhibitor-1(PAI-1) is a major down-regulator of fibrinolysis by its effect on plasmin formation and has been shown to be increased in pregnancy. In this study we examined the levels of plasma EPCR (sEPCR), TM (sTM) and PAI-1antigen in normal pregnancies (NP). A total of 82 1st trimester, 64 2nd trimester, and 78 3rd trimester samples from NP patients were used for this study. TM a cell surface protein, found primarily on endothelial cells (ECs) but also identified on trophoblasts and endometrial decidual cells (DCs) of pregnancy, is known to shed off ECs due to metalloproteinases stimulated by thrombin and pro-inflammatory cytokines or in the setting of EC damage. There are reports of increased adverse pregnancy outcome (APO) associated with high levels of plasma TM. Although the sTM level in NP is greater than non-pregnant controls contrary to other reports we did not find a statistically significant increase in TM with gestation. EPCR is a cell surface protein and is primarily on ECs and we have identified it on DCs. Like TM it is shred from ECs by metalloproteinases due to thrombin and pro-inflammatory cytokines. Cell surface TM and EPCR are central to the formation of activated protein C (APC). Our data would indicate that sEPCR statistically increased with gestation(1st trimester compared to 2nd [doubles] and 3rd [1.5 fold]. sEPCR has the property of binding free APC and decreasing its availability as an anticoagulant to degrade FVIIIa and FVa. Therefore during pregnancy the PC system is impaired by the known decrease in PS, acquired resistance to APC and the increased levels of sEPCR which would further inhibit the actions of APC. Finally we have confirmed that PAI-1 does increase in normal gestation with statistically significant rises in the PAI-1 antigen. To date, measurement of PAI-1 levels has had limited predictive value. Exploration of the relationship between PAI-1 levels, 4G/4G polymorphism and possibly PAI-1 antibodies may provide better APO risk assessment. Overall our data indicates that in normal pregnancy the prothrombotic milieu is increased by the impaired PC system by the increased level of sEPCR and the fibrinolytic system is decreased by the rise of PAI-1. The sTM although greater than non-pregnant controls does not seem to increase with NP gestation. This would suggest that serial measurements of sTM in possible problematic pregnancies may provide additional information particularly if the non-pregnant baseline value is known. This will require prospective controlled studies of larger NP and APO patients. The assessment of decreased APC plasma function may also provide added information on the risk factors for APO. This may be related in some part to the level of sEPCR.Table 11st trimester2nd trimester3rd trimester1st vs 2nd1st vs 3rd2nd vs 3rdsEPCR (ng/ml)44.9+/−2394.9+/−6262.9+/−27.3p<0.05p<0.05p<0.05sTM (ng/ml)35.2+/−21.433.5+/−10.635.3+/−33.6NSNSNSPAI-1 (ng/ml)19.3+/−12.948.4+/−23.272.4+/−27.3p<0.05p<0.05p<0.05NS=non significant

The Stress-Induced PAI-1 Expression Is Enhanced in Obese Mice: A Possible Mechanism of Stress-Associated Thrombosis in Obese Subjects.

Cardiovascular/thrombotic diseases are frequently induced by a variety of stressors. Obese patients are susceptible to thrombotic diseases associated with stress, but the underlying mechanisms are unknown. We previously reported that restraint stress to mice caused a significant induction of a primary inhibitor of fibrinolysis, plasminogen activator inhibitor-1 (PAI-1), in association with tissue microthrombosis. We have investigated the effect of obesity on the stress-induced PAI-1 expression using genetically obese mice. Male obese mice (C57BL/6J ob/ob) of 6 weeks old and their lean counterparts (C57BL/6J +/?) were placed into 50-100 ml conical centrifuge tubes fitted with multiple punctures so as to allow ventilation. The tubes were placed in horizontal holders and the animals thus maintained for a continuous period of restraint. After 2 or 20 hours of restraint, the mice (n=8) were sacrificed, and the plasma and tissues were harvested. PAI-1 antigen in plasma was measured by ELISA and PAI-1 mRNA in tissues was quantitated by competitive RT-PCR assay. Obese mice were hyperresponsive to short- and long-duration of restraint stress in the induction of PAI-1 antigen in plasma and PAI-1 mRNA in tissues, especially in their hearts and adipose tissues (Fig. 1). [Display omitted] In situ hybridization analysis of the stressed mice revealed that strong signals for PAI-1 mRNA were localized to adipocytes, cardiovascular endothelial cells, and renal glomerular cells in obese animals. Immunohistochemical analysis for fibrin revealed that renal glomerular fibrin deposition was induced by 2 hour-restraint stress in obese mice (arrow in Fig. 2B), but rare in lean mice (Fig. 2A). Quantitative evaluation of fibrin was also achieved by counting the number of fibrin-positive glomeruli in each kidney section in a blinded fashion (Fig. 2C). [Display omitted] Elevation of tumor necrosis factor-alpha (TNF-alpha) level in plasma after stress was pronounced in obese mice and pre-treatment of mice with anti-TNF-alpha antibody partially attenuated the stress-mediated induction of PAI-1 gene in adipose tissues. These results suggest that larger induction of PAI-1 may be relevant to the increased risk of stress-induced thrombosis in obese subjects and that TNF-alpha may be involved. This study presents a novel finding regarding the molecular process of the stress-induced thrombosis in obesity, and suggests that PAI-1, stress, and obesity, may be closely associated with the increased risk for cardiovascular and thrombotic diseases.

Weight reduction, but not a moderate intake of fish oil, lowers concentrations of inflammatory markers and PAI‐1 antigen in obese men during the fasting and postprandial state

In obese subjects, chronic low-grade inflammation contributes to an increased risk of metabolic abnormalities, which are reversed by weight loss. Sustained weight loss, however, is difficult to achieve and more insight into dietary approaches on anti-inflammatory responses in obese subjects is needed. In this respect, fish oil deserves attention. Eleven obese men (BMI: 30-35 kg m(-2)) received daily fish oil (1.35 g n-3 fatty acids) or placebo capsules in random order for 6 weeks. Eight subjects continued with a weight reduction study that lasted 8 weeks. Mean weight loss was 9.4 kg. At the end of each experimental period a postprandial study was performed. Relative to fasting concentrations, interleukin-6 (IL-6) levels increased by 75% 2 h and by 118% 4 h after the meal (P < 0.001), when subjects consumed the control capsules. In contrast, C-reactive protein (C-RP) concentrations decreased slightly by 0.7% and 6.6% (P = 0.046), and those of plasminogen activator inhibitor-1 (PAI-1) antigen by, respectively, 26% and 53% (P < 0.001). Tumour necrosis factor-alpha (TNF-alpha; P = 0.330) and soluble TNF-receptor concentrations (sTNF-R55 and sTNF-R75; P = 0.451 and P = 0.108, respectively) did not change. Changes relative to fasting concentrations were not significantly affected by either fish oil or weight reduction. Absolute IL-6, C-RP, sTNF-R55, sTNF-R75, and PAI-1 antigen concentrations, however, were consistently lower after weight reduction, but not after fish oil consumption. For slightly obese subjects a moderate intake of fish oil does not have the same favourable effects on markers for a low-grade inflammatory state as weight reduction.

Effects of perindopril treatment on hemostatic function in patients with essential hypertension in relation to angiotensin converting enzyme (ACE) and plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms

An imbalance in the hemostatic system is a frequent finding in untreated essential hypertension (HT), and it has been shown that treatment with angiotensin converting entyme (ACE) inhibitors improves hemostatic function. In order to elucidate the role of genetic factors, we studied hemostasis in patients with untreated and treated HT and correlated the results with ACE I/D and plasminogen activator enhibitor-1 (PAI-1) 4G/5G gene polymorphisms. Forty-three males with HT (mean age 31.7 +/- 6.8 years) were compared with 34 age and gender-matched controls. All of the patients were treated with perindopril (4 mg/day) and, after one and six months of therapy, their levels of plasma fibrinogen (Fb), t-PA antigen, PAI-1 antigen, von Willebrand factor (vWF), ACE activity and blood pressure were measured. ACE and PAI-1 genotypes were identified by means of the polymerase chain reaction on DNA isolated from peripheral blood lymphocytes. Untreated patients had significantly higher levels of Fb, PAI-1 (p < 0.01) and t-PA (p < 0.05) regardless of their ACE or PAI-1 genotypes. Perindopril reduced blood pressure regardless of ACE or PAI-1 genotype (p < 0.001). ACE II homozygotes showed the greatest decrease in ACE activity (p < 0.01) and a significant reduction in Fb levels (p < 0.05) after just one month of treatment. Analysis of the group as a whole revealed an increase in t-PA antigen levels after six months of treatment, regardless of ACE or PAI-1 genotype (p < 0.01). Our results show that essential hypertension predisposes to the procoagulant state characterized by hyperfibrinogenemia and hypofibrinolysis. Perindopril reduced fibrinogen levels in ACE II homozygotes due to its more potent inhibitory action on the renin-angiotensin system in such patients. It improved fibrinolysis by increasing t-PA levels regardless of ACE and PAI-1 genotype.

Oxidised-HDL3 induces the expression of PAI-1 in human endothelial cells. Role of p38MAPK activation and mRNA stabilization.

Modified lipoproteins have been suggested to modulate endothelial expression of plasminogen activator inhibitor-1 (PAI-1). As oxidized high-density lipoprotein (Ox-HDL) has been found in atheromatous plaques and receptors for modified HDL are present on endothelial cells, we investigated the role of Ox-HDL3 on the expression of PAI-1. Ox-HDL3 but not native HDL3, increased PAI-1 mRNA expression in endothelial cells. Furthermore, PAI-1 antigen expression and activity increased in the supernatant of cells incubated with Ox-HDL3. The intracellular pathways involved in this effect were investigated. Ox-HDL3 activated both extracellular signal-regulated kinases (ERK) 1/2 and p38 mitogen-activated protein kinase (MAPK). Moreover, incubation with specific inhibitors of these kinases showed that p38MAPK was mainly involved in the Ox-HDL3-dependent PAI-1 induction. Transient transfection experiments suggested that none of the response elements in the proximal promoter (-804 to 17) were involved in Ox-HDL3-mediated PAI-1 expression. mRNA stability experiments showed that Ox-HDL3 increased the PAI-1 mRNA half-life. In summary, Ox-HDL3 induced PAI-1 mRNA expression and antigen release through a molecular mechanism involving MAPK activation and mRNA stabilization. Thus, oxidative modification converts HDL to a prothrombotic lipoprotein species.

Obesity and impaired fibrinolysis: role of adipose production of plasminogen activator inhibitor-1.

Obesity is the central promoter of the metabolic syndrome which also includes disturbed fibrinolysis in addition to hypertension, dyslipidaemia and impaired glucose tolerance/type 2 diabetes mellitus. Plasminogen activator inhibitor-1 (PAI-1) is the most important endogenous inhibitor of tissue plasminogen activator and uro-plasminogen activator, and is a main determinant of fibrinolytic activity. There is now compelling evidence that obesity and, in particular, an abdominal type of body fat distribution are associated with elevated PAI-1 antigen and activity levels. Recent studies established that PAI-1 is expressed in adipose tissue. The greater the fat cell size and the adipose tissue mass, the greater is the contribution of adipose production to circulating PAI-1. Experimental data show that visceral adipose tissue has a higher capacity to produce PAI-1 than subcutaneous adipose tissue. Studies in human adipocytes indicate that PAI-1 synthesis is upregulated by insulin, glucocorticoids, angiotensin II, some fatty acids and, most potently, by cytokines such as tumour necrosis factor-alpha and transforming growth factor-beta, whereas catecholamines reduce PAI-1 production. Interestingly, pharmacological agents such as thiazolidinediones, metformin and AT(1)-receptor antagonists were found to reduce adipose expression of PAI-1. In addition, weight loss by dietary restriction or comprehensive lifestyle modification is effective in lowering PAI-1 plasma levels. In conclusion, impaired fibrinolysis in obesity is probably also due to an increased expression of PAI-1 in adipose tissue. An altered function of the endocrine system and an impaired auto-/paracrine function at the fat cell levels may mediate this disturbance of the fibrinolytic system and thereby increase the risk for cardiovascular disease..

The Influence of the ACE I/D Polymorphism on Plasma PAI-1 Concentrations During Exercise

1768 PURPOSE: During physical exertion, the capacity to lyse inappropriate or excessive clot (fibrinolysis) increases to protect against exertion-related ischemic events such as heart attack or stroke, which are often caused by an occlusive thrombus or clot. Increased fibrinolysis during physical exertion is partially due to a decrease in plasminogen activator inhibitor-1 (PAI-1), the main circulating inhibitor of tissue plasminogen activator. The insertion/deletion (I/D) polymorphism of the ACE gene is associated with resting plasma PAI-1 concentrations. The present study sought to investigate the METHODS: Fifty healthy, untrained males (mean + SD, age = 26 ± 5yrs, ht = 180.9 ± 8.1 cm, wt = 86.3 ± 14.6 kg) performed a maximal exercise test on a motorized treadmill. Blood samples were obtained via clean venipuncture with subjects in a semi-recumbent position prior to and immediately following exercise. Blood was drawn into an acidified citrate solution and centrifuged to obtain platelet-poor plasma. PAI-1 activity and antigen were assessed using enzyme-linked immunoadsorbant assay. DNA was extracted from whole blood and amplified by polymerase chain reaction (PCR) using allele-specific primers. PCR products were then electrophoresed in a 2% agarose gel and imaged with an ultra-violet transilluminator for genotype determination. Potential differences between subjects homozygous for the D allele (D) versus those possessing at least one I allele (I) for resting and exercise-induced PAI-1 activity and PAI-1 antigen were assessed using analysis of variance. RESULTS: There were no group differences for height, weight, age, VO2max, or peak heart rate (p>0.05). No significant difference was observed for PAI-1 antigen between groups at baseline (I = 35.8 ± 32.3 ng/ml, D = 26.4 ± 18.7 ng/ml, p>0.05) or post-exercise (I = 31.5 ± 27.6 ng/ml, D = 23.3 ± 15.6 ng/ml, p>0.05). Likewise, no differences were observed for PAI-1 activity pre-exercise (I = 12.8 ± 12.7 IU/ml, D = 13.4 ± 14.0 IU/ml, p>0.05) or post-exercise (I = 7.9 ± 8.4 IU/ml, D = 7.9 ± 9.0 IU/ml, p>0.05). No group × time interaction was observed for either PAI-1 activity or antigen. CONCLUSIONS: The ACE I/D genotype does not influence the PAI-1 response to high-intensity exercise.

Increased Expression of Plasminogen Activator Inhibitor-1 in Cardiomyocytes Contributes to Cardiac Fibrosis after Myocardial Infarction

Plasminogen activator inhibitor-1 (PAI-1) plays a critical role in tissue fibrosis by inactivating matrix metalloproteinases, which might effect on the progression of left ventricular dysfunction. However, little has been known about the expression of PAI-1 during cardiac remodeling. We used a mouse model of myocardial infarction (MI) by coronary ligation, in which the progression of left ventricular remodeling was confirmed by echocardiography. Histological examination showed that interstitial and perivascular fibrosis progressed in the post-MI (PMI) heart at 4 weeks after the procedure. We observed the dramatic induction of cardiac PAI-1 mRNA and PAI-1 antigen in plasma in the PMI mice, as compared with the sham-operated (sham) mice. In situ hybridization analysis demonstrated that strong signals for PAI-1 mRNA were localized to cardiomyocytes in the border of infarct area and around fibrous lesions, and to perivascular mononuclear cells, which seemed to be mast cells, only in hearts of the PMI mice. Importantly, less development of cardiac fibrosis after MI was observed in mice deficient in PAI-1 as compared to wild-type mice. The mRNA expression of cytokines, transforming growth factor-beta, and tumor necrosis factor-alpha, was also increased in hearts of the PMI mice, but not in the sham mice. These observations suggest that cardiomyocytes and mast cells contribute to the increased PAI-1 expression, resulting in the development of interstitial and perivascular fibrosis in the PMI heart, and that the regional induction of cytokines may be involved in this process.

The Plasminogen Activator System in Young and Lean Women with Polycystic Ovary Syndrome

The purpose of the study was to evaluate the plasminogen activator inhibitor-1 (PAI-1) levels and PAI-1 activity in young and lean women with PCOS and to compare with controls matched for age and weight. Thirty two women with PCOS and 25 weight and age-matched healthy controls participated in this study. Patients were evaluated clinically and by pelvic ultrasound and fasting blood samples were taken for hematological and biochemical tests. Fasting insulin, glucose, lipid profile, FSH, LH, PRL, testosterone, SHBG, 17-hydroxyprogesterone, androstenedione, PAI-1 antigen; PAI-1 activity, insulin sensitivity indices (HOMA and QUICKI) were measured. PAI-1 Ag and activity were significantly higher in PCOS women than healthy control group. PAI-1 levels were directly correlated with BMI, insulin levels and insulin sensitivity indices. PAI-1 activity was also correlated with insulin levels and insulin resistance. As a conclusion PAI-1 Ag levels and activity were increased in lean PCOS women and these were directly correlated with insulin resistance. The finding may contribute to evidence of increase risk of cardiovascular disease and anovulatory infertility in PCOS women.

Effects of nicorandil on endogenous fibrinolytic capacity in patients with coronary artery disease.

Nicorandil is a hybrid-type anti-anginal drug that combines a K(ATP) channel opener and a nitric oxide donor. Recently the IONA study reported that nicorandil improves the prognosis of patients with stable angina pectoris. To examine the effects of nicorandil on endogenous fibrinolysis, plasma concentrations of tissue-type plasminogen activator (t-PA) antigen, type-1 plasminogen activator inhibitor (PAI-1) antigen and PAI activity were measured in consecutive 11 patients (7 men and 4 women, mean age 63 years, ranges 41-84 years) with coronary artery disease. Nicorandil (15 mg/day) was administered orally to each patient for 2 weeks. Venous blood samples were obtained from each patient before and after the administration of the drug in the early morning before eating. There were no significant changes in the plasma concentrations of t-PA (12.4+/-1.9 to 9.8+/-1.5) or PAI-1 (26.3+/-3.9 to 21.5+/-4.9) antigens (ng/ml, mean +/- SEM) before and after nicorandil administration. On the other hand, the plasma activity of PAI (IU/ml, mean +/- SEM) decreased significantly after the treatment (12.9+/-3.2 to 5.6+/-1.9, p=0.039). It is well known that PAI activity determines the whole fibrinolytic capacity and oral administration of nicorandil decreased PAI activity in patients with coronary artery disease. This finding suggests that nicorandil improves the fibrinolytic capacity and may reduce the risk of coronary thrombus formation in such patients.

Association between obesity and a prothrombotic state: the Framingham Offspring Study.

Although obesity is associated with increased cardiovascular risk, the mechanism has not been fully explained. Since thrombosis is a critical component of cardiovascular disease, we examined the relationship between obesity and hemostatic factors. We studied 3230 subjects (55% females, mean age 54 years) without a history of cardiovascular disease in cycle 5 of the Framingham Offspring Study. Obesity was assessed by body mass index and waist-to-hip ratio. Fasting blood samples were obtained for fibrinogen, plasminogen activator inhibitor (PAI-1) antigen, tissue plasminogen activator (tPA) antigen, factor VII antigen, von Willebrand factor (VWF), and plasma viscosity. Body mass index was directly associated with fibrinogen, factor VII, PAI-1 and tPA antigen in both men and women (p>0.001) and with VWF and viscosity in women. Similar associations were present between waist-to-hip ratio and the hemostatic factors. With minor exceptions for VWF and viscosity, all associations persisted after controlling for age, smoking, total and HDL cholesterol, triglycerides, glucose level, blood pressure, and use of antihypertensive medication. The association between increased body mass index and waist-to-hip ratio and prothrombotic factors and impaired fibrinolysis suggests that obesity is a risk factor whose effect is mediated in part by a prothrombotic state.

Independent relation of vital exhaustion and inflammation to fibrinolysis in apparently healthy subjects

Objective—Vital exhaustion (VE) and a hypercoagulable state both have been associated with coronary artery disease (CAD). Candidate mechanisms by which VE predicts CAD events are impaired fibrinolysis and inflammatory changes, the latter also affecting hemostasis. We investigated whether VE and inflammation would independently relate to hemostasis.Design—Study participants were 217 (mean age ± SD, 40 ± 9 years) apparently healthy men and women working at an airplane manufacturing plant in Germany who completed the Shortened 9‐item VE Maastricht Questionnaire. All subjects had a set of classic cardiovascular risk factors assessed, and plasma levels of fibrin D‐dimer, type I plasminogen activator inhibitor (PAI‐1) antigen, C‐reactive protein (CRP), and tumor necrosis factor (TNF)‐α were measured.Results—PAI‐1 correlated with VE (r = 0.18, p = 0.009), CRP (r = 0.20, p = 0.004), and TNF‐α (r = 0.18, p = 0.009); D‐dimer correlated with CRP (r = 0.16, p = 0.018). In linear regression analyses, VE and TNF‐α independently explained 2 and 1%, respectively, of the variance in PAI‐1.Conclusion—Our study corroborates previous findings on impaired fibrinolysis in VE. The findings suggest that VE and inflammation may impair fibrinolysis by different pathways, and independently of traditional cardiovascular risk factors.

Effect of blood passage through the pulmonary circulation on fibrinolytic parameters.

The lung vasculature bed has a unique fibrinolytic potential, which has not yet been completely elucidated. We investigated the effect of blood passage through the pulmonary circulation on the values of fibrinolytic parameters in plasma. Forty-seven patients (16 women, 31 men, mean age 54 years, range 21-67 years) who had undergone elective cardiac catheterization were included in the study. The blood samples were taken simultaneously from the right atrium and the left ventricle. The following fibrinolytic parameters were measured: tissue-type plasminogen (t-PA) antigen and activity, plasminogen activator inhibitor-1 (PAI-1) antigen and activity, and euglobulin clot lysis time (ECLT). No difference was found between the samples obtained from the right atrium and the left ventricle with respect to t-PA antigen: 8.1 (6.7-11.3) vs 8.4 (5.9-11.0) ng/ml; t-PA activity: 92 (5-680) vs 62 (32-696) IU/ml; PAI-1 antigen: 8.4 (5.5-14.3) vs 8.7 (6.2-13.1) ng/ml; and ECLT: 5.5 (4.1-9.1) vs 5.6 (4.1-8.5) 1 000/min. In contrast, PAI activity decreased significantly: 7.9 (5.8-10.3) vs 7.4 (6.0-10.4) IU/ml, P < 0.01. Patients with and without pulmonary hypertension did not differ in any of measured parameters, either in the right atrium or in the left ventricle. These results show that under basal conditions fibrinolytic activity which is not attributed to t-PA is elevated in lung vasculature. Further, basal fibrinolytic activity in the lungs is not influenced by pulmonary hypertension.

4G/5G PAI-1 promoter polymorphism and acute-phase levels of PAI-1 following coronary bypass surgery: a prospective study.

The 4G/5G plasminogen activator inhibitor-1 (PAI-1) promoter polymorphism has been associated with basal PAI-1 levels, with ischemic heart disease, and with adverse prognosis in critically ill patients. We hypothesized it might also influence the acute-phase levels of PAI-1 following coronary bypass surgery. In 111 consecutive patients undergoing elective coronary bypass surgery, 4G/5G genotyping and serial plasma PAI-1 activity and antigen levels were prospectively measured before surgery, daily up to 72 h, and at discharge. The inflammatory reaction was additionally assessed by white cell count, fibrinogen, interleukin-6, and C-reactive protein levels. PAI-1 activity and antigen concentrations increased approximately two-fold after surgery, peaking at 48 hours. Carriers of the 4G-allele, compared with 5G/5G homozygotes, showed approximately 20% higher PAI-1 activity and antigen both preoperatively ( P = 0.007 and P = 0.035) and after surgery. White cell count, fibrinogen, interleukin-6, and C-reactive protein values did not differ significantly according to genotypic groups. In multivariate analysis, the 4G/5G genotype was the only significant modulator of postoperative PAI-1 activity (P = 0.003) and the main significant modulator of postoperative PAI-1 antigen (P = 0.013). No significant interaction was found between the effects of time and genotype on postoperative PAI-1. This indicates that the association between 4G/5G and acute-phase PAI-1 levels is secondary to the genotype-related difference of baseline PAI-1. Postoperative PAI-1 concentrations of patients undergoing elective coronary bypass surgery are higher in carriers of the 4G-allele than in 5G/5G homozygotes as a result of higher baseline values. Knowledge of 4G/5G status may be useful to predict acute-phase PAI-1 concentrations.

The plasminogen activator inhibitor-1 −675 4G/5G genotype influences the risk of myocardial infarction associated with elevated plasma proinsulin and insulin concentrations in men from Europe: the HIFMECH Study

Although the potential role of plasminogen activator inhibitor-1 (PAI-1) in the development of coronary artery disease is strongly supported by its biological characteristics, results of clinical studies remain controversial. To investigate whether plasma PAI-1 concentrations and the -675 4G/5G polymorphism located in the PAI-1 gene could constitute risk markers for myocardial infarction (MI). We used a European case-control study, the HIFMECH study, comparing 598 men with MI and 653 age-matched controls. Insulin resistance explained a major part of the variation in PAI-1 (24%) whereas inflammation had only a minor contribution (0.01%). For both cases and controls plasma PAI-1 concentrations were significantly higher in the North than the South, and in both regions were higher in individuals with MI compared with control subjects [overall odds ratio (OR) for a 1 SD increase=1.54, 95% confidence interval (CI) 1.34, 1.77]. This difference was observed in all the centers studied. Overall, the difference between cases and control subjects remained significant after controlling for inflammation variables (OR=1.30, 95% CI 1.08, 1.57), but lost significance after controlling for insulin resistance variables (OR=1.17, 95% CI 0.98, 1.40). The 4G allele was associated with significantly higher PAI-1 levels in cases but not controls and, taken independently, did not modify the risk of MI (P=0.9). However, a significant interaction was observed with both insulin or proinsulin and the risk of MI (P=0.05 and 0.02, respectively), but not with triglycerides or body mass index (BMI). The insulin or proinsulin effect on risk was observed only in the carriers of the 4G/4G genotype. This interaction appeared not to be mediated by plasma PAI-1 antigen concentrations (P=0.01 and 0.02 after adjustment for PAI-1 plasma levels). The interaction with proinsulin but not insulin remained statistically significant after further adjustment for other factors associated with insulin resistance (triglycerides and BMI) and C-reactive protein (P=0.01). This study suggests that PAI-1 has a role in risk of MI in the presence of underlying insulin resistance. A significant interaction between insulin or proinsulin and the -675 4G/5G polymorphism was observed in risk for MI. The mechanisms for these interactions remain to be determined.