Plasma Plasminogen Activator Inhibitor Type 1 Research Articles

Contribution of Genetic and Metabolic Syndrome to Omental Adipose Tissue PAI-1 Gene mRNA and Plasma Levels in Obesity

Plasminogen activator inhibitor type-1 (PAI-1) has already been associated with atherosclerosis; myocardial infarction; and cardiovascular disease risk factors such as obesity, insulin resistance, and dyslipidemia. However, factors regulating PAI-1 adipose tissue (AT) gene expression and plasma levels are not yet well defined. This study aims to assess the contribution of PAI-1 omental AT mRNA levels and genetic and metabolic factors to variation in plasma PAI-1 concentrations. Ninety-one non-diabetic premenopausal severely obese women (body mass index, BMI >35 kg/m(2)) undergoing bariatric surgery were phenotyped (fasting plasma glucose, lipid-lipoprotein, and PAI-1 levels) and genotyped for four PAI-1 polymorphisms. Omental AT PAI-1 mRNA levels were determined using real-time polymerase chain reaction. Stepwise regression analysis was used to identify independent PAI-1 AT mRNA and plasma level predictors. Among the variables included to the stepwise regression analysis, plasma high-density lipoprotein (HDL)-cholesterol (r = 0.38; p = 0.0004) and total cholesterol (r = 0.16; p = 0.0541) levels were the only two (out of 12) independent variables retained as predictive of PAI-1 omental AT mRNA levels, whereas BMI (r = 0.35; p = 0.0039), plasma HDL-cholesterol concentrations (r = -0.31; p = 0.0375), PAI-1 omental AT mRNA levels (r = 0.19; p = 0.0532) and PAI-1-844G/A (p = 0.0023), and rs6092 (p.A15T; p = 0.0358) polymorphisms contributed independently to plasma PAI-1 concentrations. Taken together, these variables explained 17.8% and 31.0% of the variability in PAI-1 AT mRNA and plasma levels, respectively. These results suggest that PAI-1 polymorphisms contribute significantly to PAI-1 plasma levels but do not support the notion that omental AT is one of its major source.

Effects of gliclazide on platelet aggregation and the plasminogen activator inhibitor type 1 level in patients with type 2 diabetes mellitus

Vascular complications are a common factor determining morbidity and mortality of diabetic patients. In vitro studies have revealed that gliclazide has antiplatelet activities. To clinically assess this action, we measured the effects of gliclazide on platelet activities and abnormal fibrinolysis in patients with type 2 diabetes mellitus. We studied 14 patients aged 38 to 72 years (9 men and 5 women) with type 2 diabetes mellitus who have been treated with glibenclamide in our hospital for more than 6 months. We switched from glibenclamide to gliclazide using the average ratio of the respective doses, 2.5 vs 40 mg. We titrated the dose of gliclazide to keep the glycemic control at the same level as the previous (glibenclamide) treatment. We measured 10 μmol/L serotonin–induced or 0.5 μmol/L adenosine diphosphate (ADP)–induced platelet aggregate formation by particle counting using light scattering at baseline and up to 6 months after the switch. After switching to gliclazide, platelet aggregate formation induced by serotonin was significantly reduced ( P < .05, compared with the levels observed after glibenclamide treatment). The body mass index, fasting plasma glucose, immunoreactive insulin, homeostasis model assessment of insulin resistance, hemoglobin A 1c (HbA 1c), total cholesterol, triglycerides, high-density lipoprotein cholesterol, prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin-antithrombin III complex, plasmin- α2-plasmin inhibitor complex, and plasma plasminogen activator inhibitor type 1 (PAI-1) were not changed. In the group with improved HbA 1c (n = 5), ADP-induced platelet aggregate formation and plasma PAI-1 level were significantly reduced ( P < .05, compared with the group with aggravated HbA 1c, n = 9). Multiple regression analysis showed that percentage change of ADP-induced platelet aggregate formation (standardized β = 0.540, P < .05) was independently associated with percentage change of plasma PAI-1 level in addition to percentage change of HbA 1c (standardized β = 0.657, P < .05) ( R = 0.939, P < .05) after switching to gliclazide. The other independent variants, like the final dose of gliclazide, homeostasis model assessment of insulin resistance, percentage change of prothrombin time, activated partial thromboplastin time, and total cholesterol, were not significantly associated with the percentage change of plasma PAI-1 level. These results indicate that gliclazide inhibits platelet aggregation via the serotonin pathway, independently of the metabolic control per se. Furthermore, in the patients with improved glycemic control, gliclazide could inhibit ADP-induced platelet aggregation and reduce PAI-I level. Taken together, the results show that gliclazide may be more useful for the prevention of diabetic vascular complications than glibenclamide.

Inactivation of plasminogen activator inhibitor type 1 by activated factor XII plays a role in the enhancement of fibrinolysis by contact factors in-vitro

Aims Several activated coagulation factors have been reported to enhance fibrinolysis by inactivating plasminogen activator inhibitor type 1 (PAI-1), a serine protease inhibitor. We analyzed the interaction between PAI-1 and the three serine proteases generated during contact activation of plasma, activated factor XII (FXIIa), FXIa, and kallikrein, and evaluated their effects on fibrinolysis in-vitro. Main methods Effects of kaolin on euglobulin clot lysis time (ECLT) and behavior of PAI-1 in factor-depleted plasma were analyzed. Key findings The ECLT of pooled plasma obtained from normal volunteers (designated as 100%) was shortened to 62.1 ± 3.1% by Ca 2+ (5 mM) and 29.9 ± 3.1% by kaolin. Activated protein C reversed the ECLT shortened by Ca 2+-supplementation (86.3 ± 17.4%), but did not affect the ECLT shortened by kaolin (31.4 ± 2.1%). Thus, in contrary to Ca 2+-supplementation, kaolin appeared to shorten the ECLT by a mechanism independent of thrombin generation. In three kinds of contact factor-depleted plasma, kaolin did not shorten ECLT only in FXII-depleted plasma. PAI-1 was cleaved to its inactive form in the Ca 2+ as well as the kaolin-supplemented euglobulin fraction in normal plasma, the latter of which, however, was not observed in FXII-depleted plasma. Similarly, a high molecular weight complex between FXIIa and PAI-1, as well as a cleaved form of PAI-1, was observed in kaolin-supplemented normal plasma, but neither was found in kaolin-supplemented FXII-depleted plasma. Significance PAI-1 inactivation by FXIIa appears to be a mechanism by which contact phase coagulation factors enhance fibrinolysis independently of thrombin generation.

Acute endothelial tissue plasminogen activator release in pregnancy.

Pregnancy is associated with marked changes in vascular physiology and an increased risk of thrombosis. The aim of the study was to assess the effect of pregnancy on the acute release of tissue plasminogen activator (t-PA) from the endothelium. Ten primigravida pregnant women were recruited in the third trimester of pregnancy (week 36 +/- 1) and compared with 20 age-matched non-pregnant women (day 9.8 +/- 0.3 of menstrual cycle). Blood flow and plasma fibrinolytic factors were measured in both forearms by venous occlusion plethysmography and blood sampling, respectively, during unilateral brachial artery infusions of bradykinin (100-1000 pmol min(-1)). Pregnant women had higher plasma plasminogen activator inhibitor type 1 (PAI-1) antigen concentrations (77.1 +/- 12.4 vs. 21.5 +/- 9.8 ng mL(-1); P = 0.004) that resulted in lower basal t-PA/PAI-1 ratios (0.2 +/- 0.1 vs. 0.6 +/- 0.1; P = 0.02) and plasma t-PA activity concentrations (0.17 +/- 0.02 vs. 0.58 +/- 0.06 IU mL(-1); P < 0.0004). In both groups, bradykinin caused dose-dependent increases in blood flow and local release of plasma t-PA antigen and activity (P < 0.005 for all). Both the plasma t-PA/PAI-1 ratios and the net release of active t-PA were markedly reduced in pregnant women (P < 0.05 for both). Area under the curve for net active t-PA release was reduced by 36%. Pregnancy is associated with major perturbations of endogenous fibrinolytic capacity with an overwhelming increase in plasma PAI-1 concentrations and an inadequate release of active t-PA. These prothrombotic effects may, in part, explain the increased risk of arterial and venous thrombosis in pregnant women.

Investigation of Association between Plasminogen Activator Inhibitor Type-1 (PAI-1) Gene 4G/5G Polymorphism Frequency and Plasma PAI-1 Enzyme Activity in Patients with Acute Stroke

This study was carried out to determine if there is any association between plasminogen activator inhibitor type-1 (PAI-1) gene 4G/5G polymorphism and plasma PAI-1 enzyme activity in acute stroke patients. In this study, 333 genomic DNAs (from 253 acute stroke patients and 80 healthy subjects) were analyzed. Genomic DNAs were prepared from peripheral blood using a saline method. These DNAs were amplified by PCR method using primers specific for 4G and 5G alleles. PCR products were separated by 2% agarose gel electrophoresis and visualized by a charge coupled device (CCD) camera. PAI-1 enzyme activities were measured by ELISA method. The results were evaluated statistically with Student's t-test, chi(2)-test, one-way analysis of variance, and stepwise regression analysis. In this study, frequency of PAI-1 gene 4G5G genotype was found to be low both in patients and controls. PAI-1 enzyme activities were significantly increased in acute stroke patients compared to controls. Although PAI-1 gene 4G5G genotype frequencies were low, the patients carrying this allele had highest plasma PAI-1 enzyme activity; likewise, although PAI-1 gene 4G4G genotype frequencies were high, the patients carrying this allele had lowest plasma PAI-1 enzyme activities. Homocysteine levels had a positive effect of 65% on plasma PAI-1 enzyme activities. Consequently, in this study, we may assert that PAI-1 gene, 4G4G and 5G5G genotypes, PAI-1 activity, and homocysteine level determination are significant criteria for identifying patients who are likely to develop stroke; on the other hand, a direct relation does not exist between gene polymorphism and enzyme activity.

Postprandial hypertriglyceridemia associated with inflammatory response and procoagulant state after a high-fat meal in hypertensive patients

To investigate the changes of inflammatory factors and hemostatic variable in plasma after a high-fat meal in normocholesterolemic patients with essential hypertension. A total of 60 hypertensive patients were randomly assigned to accept a single high-fat meal (group 1, n=40) or not (group 2, n=20) in the morning after an overnight fast, and 20 healthy participants (group 3) consumed a single high-fat meal on the same day. Plasma lipid profiles, high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor alpha (TNFalpha), soluble P-selectin and plasminogen activator inhibitor type 1 (PAI-1) antigen levels were measured at fasting and 4 h after meal ingestion. Postprandial triglyceride levels increased significantly in groups 1 and 3 (P<0.01), whereas levels were higher in group 1 (P<0.001). Postprandial plasma TNFalpha, hsCRP, soluble P-selectin and PAI-1 antigen levels increased in group 1 (P<0.001) but not in group 3. Postprandial plasma triglyceride level was correlated with log(hsCRP) (P<0.001), TNFalpha (P<0.001), soluble P-selectin (P<0.01) and PAI-1 antigen (P<0.05) levels, respectively. Both postprandial plasma level of soluble P-selectin and that of PAI-1 antigen were positively and significantly correlated with those of log(hsCRP) (P<0.01) and TNFalpha (P<0.001), respectively. Postprandial hypertriglyceridemia in hypertensive patients is associated with inflammatory response and procoagulant state.

WRN polymorphisms affect expression levels of plasminogen activator inhibitor type 1 in cultured fibroblasts

BackgroundRecessive mutations in WRN gene eliminate WRN protein function (helicase) and cause Werner syndrome. One of the most important clinical features of Werner syndrome patients are the premature onset and accelerated atherosclerosis process. Studies carried out on polymorphic WRN locus have shown that the alleles 1367R and 1074L confer protection for cardiovascular disease. Given that the levels of plasminogen activator inhibitor type 1 (PAI-1) were found to be significantly increased in Werner syndrome patients, is quiet possible that PAI-1 expression could be under regulation of WRN helicase. Therefore the purpose of this work was to evaluate the role of WRN polymorphism in modulating the expression of PAI-1.MethodsIn order to accomplish our aim, an array of primary cultured fibroblasts from normal adult donors was genotyped for polymorphisms of both the WRN and PAI-1 loci. In addition, steady state levels of WRN and PAI-1 were measured by semi-quantitative RT-PCR assays in such cultures. To search for the potential relationship between the lack of WRN protein and PAI-1 expression, heterozygous cultures of fibroblasts (1367RC/1074LF; WRN genotype) were treated with a molecule of interference RNA against WRN messenger RNA (mRNA).ResultsWe found that, carriers of 1367R and 1074L alleles of WRN shown to have low amounts of PAI-1 in plasma (7.56 ± 5.02), as compared with carriers of 1367C and 1074F alleles (16.09 ± 6.03). Moreover, fibroblasts from carriers with these alleles had low expression levels of PAI-1 mRNA. The treatment of heterozygous primary fibroblast cultures (1367RC/1074LF; WRN genotype) with iRNA against WRN mRNA caused PAI-1 overexpression. Treatment with normal PAI-1 inducers (TGFβ, TNFα, or insulin) in these cultures and from those with genotypes 1367CC/1074FF and 1367RR/1074FL resulted in a genotype-dependent PAI-1 expression level.ConclusionOur results suggest that polymorphisms in the WRN gene might have a significant role regulating PAI-1 levels in healthy individuals and "normal states" as well as acute or chronic stress, obesity, aging, acute inflammation, among others, where characteristic high levels of insulin, TNF α and TGFβ, could favor PAI-1 high levels in carriers with polymorphic variants (C and F alleles), beyond the levels reached by carriers with other alleles (R and L alleles).

Impact of the therapy by renin–angiotensin system targeting antihypertensive agents perindopril versus telmisartan on prothrombotic state in essential hypertension

The aim of the study was to investigate the effect of therapy by perindopril or telmisartan on endothelial/platelet function and on coagulation/fibrinolysis in 20 and 16 hypertensive patients, respectively. The measurements were carried out before and after 1 month of therapy. Both systolic blood pressure and diastolic blood pressure were reduced (P<0.001) or normalized due to each therapy. Plasma thrombomodulin (TM) and von Willebrand factor (vWF) as indicators of endothelial dysfunction, plasma beta-thromboglobulin (betaTG), platelet factor 4 (PF4), soluble P-selectin (sPsel) and soluble glycoprotein V (sGpV) as indicators of in vivo platelet activation, plasminogen activator inhibitor type 1 (PAI-1) antigen and tissue type plasminogen activator (tPA) antigen as markers of fibrinolytic activity, soluble endothelial protein C receptor (sEPCR) as a new marker of hypercoagulation and fibrinogen level as a known risk factor for vascular changes were investigated. A decrease of plasma vWF, sPsel, sGpV, PAI-1 and tPA antigen level (P<0.05, respectively) after 1 month of therapy by perindopril was observed. On the other hand, a decrease of plasma sEPCR and fibrinogen level (P<0.05, respectively) after 1 month of therapy by telmisartan was found. We failed to find changes of plasma TM, betaTG and PF4 due to any therapy investigated. The additional beneficial 'antithrombotic' effects of the renin-angiotensin system targeting agents (vasculoprotective, anti-platelet and profibrinolytic effects of perindopril and anticoagulant/rheological effects of telmisartan) may be important in terms of the favourable role of antihypertensive drugs in cardiovascular morbidity.

S35225 is a direct inhibitor of Plasminogen Activator Inhibitor type-1 activity in the blood

The increased risk of thrombotic events associated with disease states such as diabetes and hypertension has been correlated with elevated circulating levels of Plasminogen Activator Inhibitor type-1 (PAI-1). In the present study we evaluate the benzothiophene derivative S35225 in comparison with two recently described inhibitors of PAI-1 activity Tiplaxtinin and WAY140312 on a panel of PAI-1 activity assays in vitro and in vivo.In a direct chromogenic assay, S35225 has an IC50 value of 44±0.9 μM similar to that of Tiplaxtinin (34±7 μM) and of WAY140312 (39±1 μM). In a clot lysis assay however, S35225 has a significantly lower IC50 value than Tiplaxtinin and WAY140312 (0.6±0.3 versus 22±5 and 16±2 μM respectively). Using a tPA capture assay to quantify active PAI-1 in rat or human plasma, neither WAY140312, nor Tiplaxtinin attained 50% inhibition of PAI-1 activity at the highest concentration tested (1 mM); S35225 has an IC50 value of 194±30 μM against active rat PAI-1 and 260±41 μM against active human PAI-1. The ability of the compounds to inhibit endogenous active PAI-1 in the rat following intravenous administration was also tested using the tPA capture assay. Only S35225 reduced circulating active PAI-1 levels in vivo (maximum inhibition of 76±5% at 10 mg/kg and 53±5% at 3 mg/kg). In contrast to Tiplaxtinin and WAY140312, S35225 is a direct inhibitor of PAI-1 activity in vitro in rat and human plasmas where vitronectin is constitutively present as well as in vivo in the blood after an intravenous administration in the rat.

The -675 4G/5G polymorphism at the Plasminogen Activator Inhibitor 1 (PAI-1) gene modulates plasma Plasminogen Activator Inhibitor 1 concentrations in response to dietary fat consumption

The objective of the study was to determine whether Plasminogen Activator Inhibitor Type 1 (PAI-1) -675 4G/5G polymorphism is associated with the response of functional plasma PAI-1 concentrations to changes in the amount and quality of dietary fat in healthy subjects. PAI-1 is the major inhibitor of fibrinolysis, and a lower level of fibrinolytic activity could be implicated in an increased risk of IHD. Fifty-nine healthy Spanish volunteers (ten 4G/4G homozygotes, twenty-eight heterozygotes 4G/5G and twenty-one 5G/5G homozygotes) consumed three diets for periods of 4 weeks each: a SFA-rich diet (38 % fat, 20 % SFA), followed by a carbohydrate-rich diet (30 % fat, 55 % carbohydrate) and a MUFA-rich diet (38 % fat, 22 % MUFA) according to a randomized crossover design. At the end of each dietary period plasma lipid and functional plasma PAI-1 concentrations were determined. Subjects carrying the 4G allele (4G/4G and 4G/5G) showed a significant decrease in PAI-1 concentrations after the MUFA diet, compared with the SFA-rich and carbohydrate-rich diets (genotype x diet interaction: P = 0.028). 5G/5G homozygotes had the lowest plasma PAI-1 concentrations compared with 4G/4G and 4G/5G subjects (genotype: P = 0.002), without any changes as a result of the amount and the quality of the dietary fat. In summary, no differences in plasma PAI-1 concentration response were found after changes in dietary fat intake in 5G/5G homozygotes, although these subjects displayed the lowest concentrations of PAI-1. On the other hand, carriers of the 4G allele are more likely to hyper-respond to the presence of MUFA in the diet because of a greater decrease in PAI-1 concentrations.

Hyperfibrinolysis in alcoholic cirrhosis: Relative plasminogen activator inhibitor type 1 deficiency

BackgroundOver activity of the fibrinolytic system (hyperfibrinolysis) occurs in cirrhosis and has been shown to correlate with the risk of variceal hemorrhage. We have developed a model for assessing acute tissue plasminogen activator (t-PA) release in vivo in man. The aims of the study were to assess the contribution of basal and stimulated t-PA release to hyperfibrinolysis in patients with alcoholic cirrhosis. MethodsBilateral forearm blood flow and plasma fibrinolytic variables were measured in 8 patients with biopsy proven alcohol induced cirrhosis, ascites and portal hypertension, and 8 age and sex matched healthy controls during infusion of bradykinin (100–900 pmol/min; endothelium-dependent vasodilator that releases t-PA) followed by sodium nitroprusside (SNP 2–8 μg/min; a control endothelium-independent vasodilator). ResultsBaseline plasma t-PA antigen concentrations were higher in patients (14±2 vs 9±1 ng/mL; p<0.05) whereas plasma plasminogen activator inhibitor type-1 (PAI-1) antigen concentrations were similar (59±16 vs 55±11 ng/mL; p=NS). This resulted in an increased t-PA activity (3±1 vs 0±0 IU/mL; p<0.05) and reduced PAI-1 activity (9±2 vs 21±2 AU/mL; p<0.05) indicating a relative deficiency of PAI-1 in patients with cirrhosis. Bradykinin and SNP caused dose-dependent vasodilatation (p<0.001 for both) that did not differ between the two groups. Bradykinin caused a similar release of t-PA antigen (p<0.05 for both) in both patients and controls (24±17 vs 23±7 ng/100 mL/min; p=ns) without affecting PAI-1 concentrations. Local t-PA activity was increased in patients following acute stimulated t-PA release (5±1 vs 3±1 IU/mL; p<0.05). SNP caused no significant change in fibrinolytic parameters. ConclusionPatients with alcoholic cirrhosis have a higher basal plasma t-PA activity because of a failure to increase plasma concentrations of its inhibitor, PAI-1. Furthermore, despite releasing normal amounts of t-PA acutely, higher t-PA activity remained due to the relative deficiency of PAI-1. This suggests that the pathogenesis of hyperfibrinolysis in alcoholic cirrhosis is the result of a relative PAI-1 deficiency and enhanced basal t-PA release.

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

Elevated plasma plasminogen activator inhibitor-1 (PAI-1) is related to cardiovascular events, but its role in subclinical coronary microvascular dysfunction remains unknown. Thus, in the present study it was investigated whether elevated plasma PAI-1 activity is associated with coronary microvascular dysfunction in hypertensive patients. Thirty patients with untreated essential hypertension and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography. Clinical variables associated with atherosclerosis (low-density lipoprotein-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, homeostasis model assessment (HOMA-IR), and PAI-1 activity) were assessed to determine their involvement in coronary microvascular dysfunction. Adenosine triphosphate (ATP)-induced hyperemic MBF and coronary flow reserve (CFR) were significantly lower in hypertensive patients than in healthy controls (ATP-induced MBF: 2.77+/-0.82 vs 3.49+/-0.71 ml x g(-1) x min(-1); p<0.02 and CFR: 2.95 +/-1.06 vs 4.25+/-0.69; p<0.001). By univariate analysis, CFR was positively correlated with HDL-cholesterol (r=0.46, p<0.02), and inversely with HOMA-IR (r=-0.39, p<0.05) and PAI-1 activity (r=-0.61, p<0.001). By multivariate analysis, elevated PAI-1 activity remained a significant independent determinant of diminished CFR. Elevated plasma PAI-1 activity was independently associated with coronary microvascular dysfunction, which suggests that plasma PAI-1 activity is an important clue linking hypofibrinolysis to the development of atherosclerosis.

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

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. 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. 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.

Increased plasminogen activator inhibitor type-1 (PAI-1) in the heart as a function of age

Heart failure is associated with advanced age and insulin resistance and is thought to be exacerbated by cardiac fibrosis. Plasminogen activator inhibitor type-1 (PAI-1) has been strongly implicated as a determinant of fibrosis in diverse organs and tissues. Its concentration is increased in blood, and its expression is increased in vessel walls in association with insulin resistance. Accordingly, we sought to determine whether expression of PAI-1 in the heart increases as a function of age of 10 week old and 20 week old normal and insulin resistant transgenic mice thereby potentially predisposing to heart failure. Results obtained indicate that PAI-1 content increases significantly in the heart as a function of age by more than 60%. The increases are much greater than those that can be accounted for by the modest, and statistically insignificant increases in the concentrations of PAI-1 in plasma that were observed to occur as a function of age as well. Thus, PAI-1 increases in the heart is a function of age, occurs in insulin resistant and non-insulin resistant mice, and may contribute to fibrosis predisposing to heart failure associated with advanced age, particularly when insulin resistance is present.

Significant differential effects of lower doses of hormone therapy or tibolone on markers of cardiovascular disease in post-menopausal women: a randomized, double-blind, crossover study

We have previously reported that lower doses of hormone therapy (L-HT) and tibolone have different effects on markers of cardiovascular disease when compared with conventional doses of HT. The objective was to compare the effects of L-HT and tibolone on lipid profile, vasodilation, and factors associated with inflammation and haemostasis. Forty-one women received a combination of micronized progesterone 100 mg with conjugated equine estrogen 0.3 mg vs. tibolone 2.5 mg alone daily in random order during 2 months with 2 months washout period. When compared with L-HT, tibolone significantly reduced total cholesterol (P<0.001), triglyceride (P<0.001), HDL cholesterol (P<0.001) levels, and triglyceride/HDL cholesterol ratios (P=0.004) except total cholesterol/HDL cholesterol ratios. Tibolone improved flow-mediated response to hyperaemia from baseline values (P<0.001) by a similar magnitude to L-HT. L-HT and tibolone did not increase high-sensitivity C-reactive protein relative to baseline values. L-HT reduced antithrombin III from baseline values (P=0.037), compared with tibolone showing no changes. However, there was no difference between either. In contrast, tibolone increased pro-thrombin fragment 1+2 (F1+2) from baseline values (P=0.002), compared with L-HT showing no changes. Tibolone significantly reduced plasma plasminogen activator inhibitor type 1 (PAI-1) antigen levels from baseline values (P=0.004), compared with L-HT showing no changes. The effects of L-HT and tibolone on F1+2 and PAI-1 were significantly different (P=0.045 and P=0.008, respectively). Both tibolone and L-HT improved flow-mediated response by a similar magnitude and did not significantly increase high-sensitivity C-reactive protein. However, tibolone significantly reduced PAI-1, but increased F1+2 more than L-HT.

Increased plasma fibrinolytic activity in bleeding gastrointestinal angiodysplasia

Gastrointestinal angiodysplasia is a major cause of recurrent bleeding. Haemostatic abnormalities have been implicated in the haemorrhage from these common vascular lesions but their precise contribution remains to be established. Our aim was to investigate whether bleeding angiodysplasia is associated with any specific coagulation disorder. Clinical features and blood samples were prospectively obtained from 21 patients with bleeding gastrointestinal angiodysplasia 3 months after the last episode of haemorrhage. Plasma levels of von Willebrand factor, D-dimer, plasminogen activator inhibitor type 1 (PAI-1), tissue-plasminogen activator activity, tissue factor pathway inhibitor and activated factor VII (FVIIa-rTF) were measured. A group of 14 patients with bleeding duodenal ulcer were similarly studied as controls. Mean plasma von Willebrand factor levels were higher in angiodysplasia patients (208+/-12%) than in controls (143+/-11%) (P<0.05). D-dimer levels (661+/-80 ng/ml) and tissue-plasminogen activator activity levels (2.04+/-0.14 IU/ml) were also higher than in controls: 395+/-99 ng/ml and 1.6+/-0.1 IU/ml, respectively (P<0.05), whereas levels of PAI-1, FVIIa-rTF and tissue factor pathway inhibitor were similar in both groups. However, PAI-1 levels (31.5+/-11 ng/ml) were lower in high-bleeding-rate angiodysplasia (more than two bleeding episodes/year) than in low-bleeding-rate angiodysplasia (< or = 2 bleeding episodes/year) (PAI-1 47+/-14 ng/ml) (P<0.05). In a multivariate regression analysis, the plasma level of PAI-1 was a predictor of haemorrhage from angiodysplasia (P<0.05). Increased plasma fibrinolytic activity may contribute to bleeding from angiodysplasia. Low plasma PAI-1 levels constitute a risk factor for bleeding tendency in patients with angiodysplasia.

Is the Effect of Antihypertensive Drugs on Platelet Aggregability and Fibrinolysis Clinically Relevant?

Hypertension is associated with decreased fibrinolytic potential, mainly expressed as elevated plasma plasminogen activator inhibitor type 1 (PAI-1) levels, and increased platelet aggregability, which may account in part for the increased risk of atherosclerosis and its clinical complications in hypertensive patients. The effects of antihypertensive drugs on this prothrombotic state have been investigated and controversial findings have been reported, possibly because of differences in study designs, patients selected, and methodology used. Scarce and conflicting data exist about the effects of diuretics and beta-adrenoceptor antagonists on the fibrinolytic system, whereas ACE inhibitors have generally been reported to improve the fibrinolytic balance by decreasing plasma PAI-1 levels, calcium channel antagonists have been shown to increase tissue plasminogen activator (tPA) activity, and angiotensin II type 1 (AT(1)) receptor antagonists seem to exert neutral effects. beta-Adrenoceptor antagonists, calcium channel antagonists, and AT(1)-receptor antagonists have been reported to exert anti-aggregatory effects on platelets, while contrasting data exist about the influence of ACE inhibitors. Clinical implications of the changes induced by antihypertensive drugs on the fibrinolytic balance and platelet function are still debated. In particular, the question of whether these changes may translate into different degrees of cardiovascular protection in hypertensive patients remains unanswered. While awaiting more information from clinical trials, the choice of antihypertensive drugs, particularly in high-risk patients, should take into account effects beyond their BP-lowering efficacy. Selected agents should have a favorable, or at least neutral, impact on fibrinolytic function and platelet activity.

Effects of Cilnidipine on Fibrinolysis in Chinese Hypertensive Patients

Hypertension is an important risk factor for myocardial infarction and stroke. Accumulating data support the association of blood pressure and impairment of fibrinolysis in hypertensive patients. Fibrinolysis plays a pivotal role in atherogenesis, but there are few studies that focus on evaluating the effect of calcium channel antagonists on fibrinolysis in hypertensive patients, and the results are controversial. The aim of this study was therefore to investigate the effects of cilnidipine on fibrinolysis in Chinese hypertensive patients. This study was an open-label, paired trial that included 43 patients with mild-to-moderate hypertension. After a 2-week placebo washout period, patients were treated with cilnidipine 5mg daily for 8 weeks. Venous blood was taken before and after treatment between 8am and 9am, after an overnight fast. Plasma tissue plasminogen activator (tPA) antigen and plasminogen activator inhibitor type 1 (PAI-1) antigen were measured by ELISA and plasma angiotensin II was measured by radioimmunoassay. After treatment with cilnidipine for 8 weeks, plasma tPA antigen level increased significantly (from 12.12 +/- 6.77 ng/mL pre-treatment to 16.12 +/- 11.89 ng/mL post-treatment, p < 0.05), and the PAI-1 antigen level remained unaffected. There were no significant changes in plasma angiotensin II. Systolic and diastolic blood pressures were significantly decreased without changes in heart rate. These data suggest that in hypertensive patients, a population with impaired fibrinolysis, cilnidipine may improve the fibrinolytic balance, and that cilnidipine is effective in treating hypertension without causing reflex tachycardia.

Plasma Fibrinolysis Inhibitor Levels in Acute Stroke Patients with Thrombolysis Failure

Background and PurposeThrombolytics-induced recanalization fails in a significant portion of patients with ischemic stroke, which is partly due to the resistance of clots to lysis by thrombolytic agents. The pretreatment level of endogenous fibrinolysis inhibitors may affect such thrombolysis failure.MethodsWe studied 43 stroke patients whose arterial recanalization had been evaluated by angiography, and whose blood had been obtained prior to the administration of thrombolytic agents. Plasma samples from 34 healthy volunteers were used as normal controls. Plasminogen activator inhibitor type 1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) levels were quantified using an enzyme-linked immunosorbent assay.ResultsArteries were recanalized [Thrombolysis in Myocardial Infarction (TIMI) grade 2 or 3] in 30 patients, but not (TIMI grade 0 or 1) in the other 13. The plasma PAI-1 level was significantly higher in patients without recanalization (nonrecanalization) than in those with recanalization and in normal controls. The TAFI levels did not differ among the groups.ConclusionsThe pretreatment PAI-1 levels are increased in acute stroke patients with thrombolysis failure.

Effect of amlodipine–atorvastatin combination on fibrinolysis in hypertensive hypercholesterolemic patients with insulin resistance

The aim of this study was to evaluate the effect of the amlodipine-atorvastatin combination on plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) activity in hypercholesterolemic, hypertensive patients with insulin resistance. The study population included 45 patients, aged 41 to 70 years, with mild to moderate essential hypertension (diastolic blood pressure [BP] > or = 95 and < or = 105 mm Hg), hypercholesterolemia (total cholesterol > 200 and < 350 mg/dL), and insulin resistance (HOMA index > 2.5) After a 4-week wash-out period, they were randomized to amlodipine (5 mg) or atorvastatin (20 mg) or their combination at the same oral dosage for 12 weeks in three cross-over periods each separated by a 4-week placebo period (3 by 3 latin square design). At the end of the placebo wash-out and of each treatment period, office BP, total cholesterol, PAI-1, and t-PA activity were evaluated. The amlodipine-atorvastatin combination, in addition to the expected hypocholesterolemic effect, produced: 1) a greater decrease in PAI-1 activity (-10.2 U/mL, P <.01 v placebo) and an even greater increase in t-PA activity (+0.26 U/mL, P <.01 v placebo) than amlodipine (-0.5 U/mL for PAI-1, P = not significant; +0.17 U/mL for t-PA, P <.01 v placebo) and atorvastatin alone (respectively, -9.9 U/mL, P <.01 v placebo and +0.08 U/mL, P <.05 v placebo); and 2) a greater systolic BP/diastolic BP mean reduction (-22/17 mm Hg, P <.005 v placebo) than amlodipine (-18/14 mm Hg, P <.01 v placebo) and atorvastatin alone (-2.8/3.8 mm Hg, P <.05 v placebo only for diastolic BP). The positive effect on fibrinolytic balance and BP control observed suggests that in hypertensive, hypercholesterolemic patients with impaired fibrinolysis, the combination of amlodipine and atorvastatin could be the treatment of choice.