Plasminogen Activator Inhibitor-1 Antigen Levels Research Articles

Fibrinolysis Assessment with Tpa-ROTEM in Patients with Bleeding Disorders of Unknown Cause (BDUC)

Background: In 40-70% of patients referred to the hematologist for evaluation of bleeding symptoms, no cause for their increased bleeding tendency can be found using currently available hemostasis laboratory tests. This group is classified as patients with bleeding disorder of unknown cause (BDUC). The lack of clear guidelines concerning diagnosis, management and genetic counseling in BDUC-patients poses a challenge for patients, family members and treating physicians. Several hemostasis assays have been investigated in BDUC-patients, but little is known about the role of the fibrinolytic pathway in this patient group. This can be explained by the lack of standardized fibrinolysis tests and the limited availability of these tests in laboratories. To further unravel potential bleeding mechanisms in BDUC, in the present study we assessed fibrinolysis in BDUC patients by using a global whole blood tPA ROTEM assay and determining of individual fibrinolysis proteins. Aim: To investigate the capacity of the tPA-ROTEM assay to detect fibrinolytic abnormalities in BDUC-patients and to correlate these findings with fibrinolytic protein activity levels in plasma. Methods: Data from patients referred to the hematologist for bleeding evaluation and included in the Prediction of Evaluation in Adult Hematologic Patients with Bleeding Tendencies (ProBe-AHP) study (METC:14-4-036) were used. BDUC-patients were identified based on (1) a clinically relevant increased bleeding tendency and (2) no abnormalities in extended hemostasis laboratory testing. tPA-ROTEM assay was done according to the in 2016 validated and published method on the ROTEM device. Fibrinolysis protein plasma levels, including plasminogen, plasminogen activator inhibitor 1 (PAI-1) antigen and activity, tissue plasminogen activator (tPA) antigen, alpha2-antiplasmin and thrombin activatable fibrinolysis inhibitor (TAFI), were measured using ELISA assays. Pre-specified definitions of hyper- and hypofibrinolysis as measured by tPA-ROTEM were applied to identify hyper- and hypofibrinolytic profiles. Results: tPA-ROTEM identified a hyperfibrinolytic profile in 15/73 (20%) of BDUC-patients, a hypofibrinolytic profile in 16/73 (22%) of BDUC-patients and a normal profile in 42 BDUC-patients (58%). Plasminogen activity inhibitor 1 (PAI-1) activity and antigen levels and α2-antiplasmin levels were lower in BDUC-patients with a hyperfibrinolytic profile compared to BDUC-patients with a hypofibrinolytic profile. No statistically significant correlations between tPA-ROTEM parameters and fibrinolysis protein plasma levels were identified using multivariate regression analysis. Conclusion: tPA-ROTEM identified a hyperfibrinolytic profile in 20% of BDUC-patients. In this group, the lower PAI-1 activity and antigen levels and lower α2-antiplasmin levels are in concordance with the expected changes in case of hyperfibrinolysis. These findings indicate that these fibrinolysis protein plasma levels are within the lower functional range of their distribution, shifting the balance towards increased clot lysis leading to an increased bleeding tendency. These findings might deliver evidence to the use of antifibrinolytic therapies in BDUC-patients in case of bleeding or interventions. Informed consent and approval from the medical-ethical committee from Maastricht (METC azM/UM) were obtained.

Investigation of Plasminogen Activator Inhibitor-1 (PAI-1) 4G/5G promoter polymorphism and other thrombophilia genes in patients with acute pulmonary embolism

Abstract Background Venous thromboembolism (VTE) is a serious threat to life and health, commonly known as the silent killer. Recent study has found that VTE is a polygenetic disease and more than 60% of deep vein thrombosis risk is influenced by genetic factors [1]. PAI-1 is a serine protease with negative feedback to fibrinolysis, activating and inhibiting coagulation [2]. The aim of this study was to elucidate the clinical impact of the PAI-1 4G/5G polymorphism and other thrombophilia in patients with acute PE. Methods A total of 58 subjects with acute PE and 60 healthy controls, were recruited in Institute of Cardiology. The accuracy of the RT-PCR method for detecting F5 G1691A (FVL) and PAI-1 4G/5G polymorphisms was evaluated by using sequencing method as the gold standard. Moreover, the association of the PAI-1 4G/5G polymorphism with susceptibility, treatment efficacy and recurrence status were explored. Eventually, we evaluated the association with inherited thrombophilia genes, such as the coagulation Factor V Leiden, prothrombin G20210A, FGB-455 G/A and methylenetetrahydrofolate reductase C677T and 1298 A/C. Results It was noted that the vast majority of patients with acute PE (87.9%) present polymorphism in the PAI-1 gene (29.3% homozygous (4G/4G) and 58.6% heterozygous (5G/4G)). Eleven patients out of 58 (19% of patients) showed factor V Leiden mutation and 19 patients out of 58 (32,7% of patients) showed mutation in FGB-455 G/A (2 homozygotes); MTHFR C677T gene mutation was found in 55,2%, while prothrombin 20210A gene mutation was presented in 6 patients (10.3% of patients). Nine patients (15,5% of patients) presented with chronic complication of VTE and 38.7% of patients showed recurrent pulmonary embolism. More than a half of patients (51.9%) had multiple gene mutation and only one presented with mutations in three studied genes. It showed a significant difference in the occurrence of other thromboses in the body and significant increase in the recurrence of pulmonary embolism and residual complications in these patients. It was also observed that individuals with the 4G/5G genotype had lower neutrophil counts and neutrophil-to-lymphocyte ratio (NLR) than the 5G/5G genotype. Furthermore, it was underlined that the patients with the 5G/5G genotype were more likely to achieve complete recanalization compared to the 4G/4G genotype. Individuals carrying the 5G/5G genotype were more likely to develop a recurrence-free status as compared to those with the 4G/4G or 4G/5G genotypes. PAI-1 antigen levels in the VTE group were significantly higher than those in the HC group. Conclusion The PAI-1 4G/5G polymorphism has potential value in assessing the prognosis of patients with VTE. This study has laid the foundation for the application of PAI-1 4G/5G polymorphism in the personalized management and monitoring of patients with VTE. According to this study results PAI-1 4G/5G polymorphism could be included in laboratory testing panel of thrombophilia.

Effects of COVID-19 disease on PAI-1 antigen and haematological parameters during disease management: A prospective cross-sectional study in a regional Hospital in Ghana.

Individuals with COVID-19 experience thrombotic events probably due to the associated hypofibrinolysis resulting from the upregulation of plasminogen activator inhibitor-1 (PAI-1) antigen. This study evaluated plasma PAI-1 antigen levels and haematological parameters before treatment and after recovery from severe COVID-19 in Ghana. This cross-sectional study was conducted at Sunyani Regional Hospital, and recruited 51 patients who had RT-PCR-confirmed SARS-CoV-2. Participants' sociodemographic data and clinical characteristics were taken from the hospital records. Venous blood was taken before COVID-19 treatment commenced for FBC, PAI-1 and ferritin assays. FBC was assessed using an automated haematology analyzer, whilst plasma PAI-1 Ag and serum ferritin levels were assessed with sandwich ELISA. All the tests were repeated immediately after participants recovered from COVID-19. Of the 51 participants recruited into the study, 78.4% (40) had non-severe COVID-19 whiles 21.6% (11) experienced a severe form of the disease. Severe COVID-19 participants had significantly lower haemoglobin (g/dL): 8.1 (7.3-8.4) vs 11.8 (11.0-12.5), p<0.001; RBC x 1012/L: 2.9 (2.6-3.1) vs 3.4 (3.1-4.3), p = 0.001; HCT%: 24.8 ± 2.6 vs 35.3 ± 6.7, p<0.001 and platelet x 109/L: 86.4 (62.2-91.8) vs 165.5 (115.1-210.3), p<0.001, compared with the non-severe COVID-19 group. But WBC x 109/L: 11.6 (9.9-14.2) vs 5.4 (3.7-6.6), p<0.001 and ferritin (ng/mL): 473.1 (428.3-496.0) vs 336.2 (249.9-386.5), p<0.001, were relatively higher in the participants with severe COVID-19 than the non-severe COVID-19 counterparts. Also, the severely ill SARS-CoV-2-infected participants had relatively higher plasma PAI-1 Ag levels (ng/mL): 131.1 (128.7-131.9) vs 101.3 (92.0-116.8), p<0.001, than those with the non-severe form of the disease. Participants had lower haemoglobin (g/dL): 11.4 (8.8-12.3 vs 12.4 (11.5-13.6), p<0.001; RBC x 1012/L: 3.3 (2.9-4.0) vs 4.3 (3.4-4.6), p = 0.001; absolute granulocyte count x 109/L: 2.3 ± 1.0 vs 4.6 ± 1.8, p<0.001, and platelet x 109/L: 135.0 (107.0-193.0) vs 229.0 (166.0-270.0), p<0.001 values at admission before treatment commenced, compared to when they recovered from the disease. Additionally, the median PAI-1 Ag (ng/mL): 89.6 (74.9-100.8) vs 103.1 (93.2-128.7), p<0.001 and ferritin (ng/mL): 242.2 (197.1-302.1) vs 362.3 (273.1-399.9), p<0.001 levels were reduced after a successful recovery from COVID-19 compared to the values at admission. Plasma PAI-1 Ag level was higher among severe COVID-19 participants. The COVID-19-associated inflammation could affect red blood cell parameters and platelets. Successful recovery from COVID-19, with reduced inflammatory response as observed in the decline of serum ferritin levels restores the haematological parameters. Plasma levels of PAI-1 should be assessed during the management of severe COVID-19 in Ghana. This will enhance the early detection of probable thrombotic events and prompts Physicians to provide interventions to prevent thrombotic complications associated with COVID-19.

Changes in fibrinolytic activity and coagulation factors after epicardial left atrial appendage closure in patients with atrial fibrillation.

The left atrial appendage (LAA) is known to be the primary source of thrombus formation in atrial fibrillation (AF). We investigate whether epicardial LAA occlusion (LAAO) from the cardiovascular system has an effect on coagulation and prothrombotic status in AF. Twenty-two patients with nonvalvular AF, who were not currently receiving oral anticoagulation (OAC) therapy, participated in a single-center prospective study. We measured fibrinogen and plasminogen levels along with plasma fibrin clot permeability, clot lysis time (CLT) and endogenous thrombin potential (ETP) before the LAAO procedure, at discharge and 1 month afterward. One month after the LAAO procedure, plasma fibrin clot permeability improved by 39.3% as measured by clots prepared from peripheral blood (P=0.019) and also after adjustment for fibrinogen (P=0.027). Higher plasma fibrin clot permeability was associated with improved clot susceptibility to lysis (r=-0.67, P=0.013). CLT was reduced by 10.3% (P=0.0020), plasminogen activator inhibitor-1 antigen levels were reduced by 52% (P=0.023) and plasminogen activity was increased by 8.9% (P=0.0077). A trend toward decreased thrombin generation, reflected by a decreased ETP and peak thrombin generated was also observed 1 month after LAAO procedure (P=0.072 and P=0.087, respectively). No differences were observed in tissue-type plasminogen activator and thrombin-activatable fibrinolysis inhibitor plasma levels (both P>0.05). Obtained results seem to confirm that LAA plays a key role in thrombogenesis. Elimination of LAA from the circulatory system may improve fibrin clot permeability and susceptibility to fibrinolysis in peripheral blood.

The role of the platelet pool of Plasminogen Activator Inhibitor-1 in well-controlled type 2 diabetes patients.

BackgroundThe main inhibitor of the fibrinolytic system, Plasminogen Activator Inhibitor -1 (PAI-1), irreversibly binds tissue-type Plasminogen Activator (t-PA) and thereby inhibits the protective action of tPA against thrombus formation. Elevated levels of plasma PAI-1 are associated with an increased risk of cardiovascular events and are observed in subjects with type 2 diabetes (T2D) and obesity. Platelets contain the majority of PAI-1 present in blood and exhibit the ability to synthesis active PAI-1. Diabetic platelets are known to be hyper-reactive and larger in size; however, whether these features affect their contribution to the elevated levels of plasma PAI-1 in T2D is not established.ObjectivesTo characterize the PAI-1 antigen content and the mRNA expression in platelets from T2D subjects compared to obese and lean control subjects, in order to elucidate the role of platelet PAI-1 in T2D.MethodsNine subjects with T2D and obesity were recruited from Primary Care Centers together with 15 healthy control subjects (8 lean subjects and 7 with obesity). PAI-1 antigen levels in plasma, serum and platelets were determined by ELISA, and PAI-1 mRNA expression was analyzed by qPCR.ResultsThere was no significant difference in PAI-1 mRNA expression or PAI-1 antigen in platelets in T2D subject in comparison to obese and lean control subjects. An elevated level of plasma PAI-1 was seen in both T2D and obese subjects. PAI-1 gene expression was significantly higher in both obese groups compared to lean.ConclusionSimilar levels of protein and mRNA expression of PAI-1 in platelets from T2D, obese and lean subjects indicate a limited role of platelets for the elevated plasma PAI-1 levels. However, an increased synthesis rate of mRNA transcripts in platelets from T2D and an increased release of PAI-1 could also result in similar mRNA and protein levels. Hence, synthesis and release rates of PAI-1 from platelets in T2D and obesity need to be investigated to further elucidate the role of platelets in obesity and T2D.

PAI-1 5G/5G genotype is an independent risk of intracranial hemorrhage in post-lysis stroke patients.

ObjectiveThrombolysis by recombinant tissue plasminogen activator (rt‐PA) is the main pharmacological therapy in acute ischemic stroke (IS); however, it is only effective in a subset of patients. Here we aimed to investigate the role of plasminogen activator inhibitor‐1 (PAI‐1), an effective inhibitor of t‐PA, and its major polymorphism (PAI‐1 4G/5G) in therapy outcome.MethodsStudy population included 131 consecutive IS patients who all underwent thrombolysis. Blood samples were taken on admission, 1 and 24 h after rt‐PA infusion. PAI‐1 activity and antigen levels were measured from all blood samples and the PAI‐1 4G/5G polymorphism was determined. Clinical data including NIHSS were registered on admission and day 1. ASPECTS was assessed using CT images taken before and 24 h after thrombolysis. Intracranial hemorrhage (ICH) was classified according to ECASS II. Long‐term outcome was defined 90 days post‐event by the modified Rankin Scale (mRS).ResultsPAI‐1 activity levels dropped transiently after thrombolysis, while PAI‐1 antigen levels remained unchanged. PAI‐1 4G/5G polymorphism had no effect on PAI‐1 levels and did not influence stroke severity. PAI‐1 activity/antigen levels as measured on admission were significantly elevated in patients with worse 24 h ASPECTS (<7). Logistic regression analysis including age, sex, NIHSS on admission, BMI, history of arterial hypertension, and hyperlipidemia conferred a significant, independent risk for developing ICH in the presence of 5G/5G genotype (OR:4.75, 95%CI:1.18–19.06). PAI‐1 levels and PAI‐1 4G/5G polymorphism had no influence on long‐term outcomes.InterpretationPAI‐1 5G/5G genotype is associated with a significant risk for developing ICH in post‐lysis stroke patients.

Relationship among HbA1c and Some Markers of Endothelial Damage in Type 2 Diabetes Mellitus

Background: A number of processes regulating the thrombolytic balance are impaired in diabetic patients as a result of dysfunction of endothelial cells leading to a hypercoagulative state. Von Willebrand factor (VWF) is an important marker of endothelial dysfunction. Plasminogen activator inhibitor-1 antigen (PAI-1-Ag), the major physiological inhibitor of tissue plasminogen activator (tPA), is mainly produced by endothelium. The aim of this study is to measure plasma levels of von Willebrand factor, Plasminogen activator inhibitor-1 antigen in type 2 diabetes mellitus patients and to correlate with glycated haemoglobin (HbA1c).&#x0D; Study Design: This prospective cohort study was conducted on 30 diagnosed type 2 DM patients who were about to start treatment.&#x0D; Place and Duration of Study: Medical outpatient (MOP) clinic of Enugu State University of Science and Technology Teaching Hospital (ESUTTH), between January and December 2016.&#x0D; Methodology: We included 30 patients (13 men, 17 women; age range 40-80 years) with type 2 diabetes mellitus. Blood samples were drawn from the patients before they commenced treatment, six months into the treatment and at twelve months of the treatment. Blood samples were also drawn from 25 age matched non diabetic patients. Plasma von Willebrand factor and Plasminogen activator inhibitor-1 antigen levels were determined by Enzyme linked immunosorbent assay. Glycated haemoglobin (HbA1c) and fasting blood sugar (FBS) levels were also evaluated along with them.&#x0D; Results: This study was conducted on 30 type 2 DM patients consisting of 13 males and 17 females. At treatment naïve, mean levels of vWF were significantly increased (45.48 +/- 6.46) in male type 2 Diabetic patients compared to the control (20.45 +/- 0.26). Six months into treatment mean levels of vWF were significantly increased (48.18 +/- 4.99) in female type 2 Diabetic patients compared to the control (37.64 +/- 7.93). The plasma levels of vWF were significantly and positively correlated with HbA1c at six months into treatment in male type 2 DM patients. The plasma levels of vWF were also significantly and positively correlated with PAI-1 at six and twelve months into treatment in both genders.&#x0D; Conclusion: There was strong significant positive correlation between plasma levels of vWF and PAI-1 in type 2 diabetes mellitus patients.

SA47GENETIC PREDISPOSITION TO VITAMIN B12 AND FOLATE DEFICIENCY LEADS TO THE DEVELOPMENT OF DEPRESSION IN POSTPARTUM PERIOD BY HYPO-METHYLATION OF SEROTONIN TRANSPORTER AND MONOAMINE OXIDASE-A GENE LOCI

Plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator (uPA) play a crucial role in cancer progression. In the present study we examined the regulation of PAI-1 and uPA expressions in normal prostate epithelial cells (PrEC) and the prostate cancer cell lines LNCaP, DU-145, and PC-3. The antigen and mRNA levels of PAI-1 were down-regulated in cancer cells, especially in LNCaP and DU-145. In the presence of proinflammatory cytokines, an increase of PAI-1 mRNA levels was observed in PrEC, LNCaP and PC-3, but not in DU-145 cells. Treatment with demethylating agent, 5-aza-2′-deoxycytidine increased the level of PAI-1 transcript in DU-145 cells and restored the inducing effect of cytokines on PAI-1 expression. An aberrant methylation of PAI-1 promoter in DU-145 and LNCaP cells was shown by methylation-sensitive high resolution melting (MS-HRM) analysis. PAI-1 methylation was also significantly increased in tumor samples (23.2 ± 1.7%) in comparison to adjacent non-tumor tissue (6.0 ± 0.8%). Furthermore, the expression of uPA was increased in high invasive cell lines DU-145 and PC-3 in comparison to PrEC and low invasive LNCaP cells. MS-HRM analysis revealed aberrant methylation of uPA promoter in LNCaP cells, but not in PrEC, DU-145 and PC-3 cells, as well as in normal and prostate cancer tissue samples. In conclusion, the study shows that PAI-1 and uPA expressions were changed in opposite directions in high invasive prostate cancer cell lines resulting in a strong decrease of PAI-1/uPA ratio, which may indicate a shift towards proteolytic activities. Methylation of the PAI-1 gene is suggested as one of the molecular mechanisms involved in the cancer-associated down-regulation of the PAI-1 expression.

Association between plasminogen activator inhibitor-1 and cardiovascular events: a systematic review and meta-analysis

BackgroundSmall studies have implicated plasminogen activator inhibitor-1 (PAI-1) as a predictor of cardiovascular events; however, these findings have been inconsistent.We sought out to examine the potential role of PAI-1 as a marker for major adverse cardiovascular events (MACE).MethodsWe systematically reviewed all indexed studies examining the association between PAI-1 and MACE (defined as death, myocardial infarction, or cerebrovascular accident) or restenosis. EMBASE, Web of Science, Medline, and the Cochrane Library were searched through October 2016 to identify relevant studies, supplemented by letters to authors and review of citations. Studies reporting the results of PAI-1 antigen and/or activity levels in association with MACE in human subjects were included.ResultsOf 5961 articles screened, we identified 38 articles published between 1991 to 2016 that reported PAI-1 levels in 11,557 patients. In studies that examined PAI-1 antigen and activity levels, 15.1% and 29.6% of patients experienced MACE, respectively. Patients with MACE had higher PAI-1 antigen levels with a mean difference of 6.11 ng/mL (95% CI, 3.27-8.96). This finding was similar among patients with and without known coronary artery disease. Comparatively, studies that stratified by PAI-1 activity levels were not associated with MACE. In contrast, studies of coronary restenosis suggest PAI-1 antigen and activity levels are negatively associated with MACE.ConclusionsElevated plasma PAI-1 antigen levels are associated with MACE. Definitive studies are needed to ascertain if PAI-1 acts simply as a marker of risk or if it is indeed a bona fide therapeutic target.

Differential effect of the ultra-low dose and standard estrogen plus dydrogesterone therapy on thrombin generation and fibrinolysis in postmenopausal women.

The objective of this study was to estimate the effects of different doses of oral hormone therapy (HT) on thrombin generation and fibrinolytic activity in postmenopausal women after 12 months of treatment. Thrombin generation, fibrinolysis activators and inhibitors were determined before and after 12 months of treatment. Participants (180) were assigned (1:1:1) as follows: (1) standard HT group, 17β-estradiol (1 mg/day) with dydrogesterone (5 mg/day); (2) ultra-low dose HT group, 17β-estradiol (0.5 mg/day) with dydrogesterone (2.5 mg/day); (3) control group, no treatment. The standard HT led to a higher concentration of prothrombin 1 + 2 fragment (by 5.8%) with lower antithrombin activity (by 6.1%). Compared with baseline, we observed a reduction in mean antithrombin activity in the standard HT group and increases in mean levels of prothrombin 1 + 2 fragment in two HT groups. We found decreases after treatment in both standard and ultra-low dose HT groups in plasminogen activator inhibitor-1 (PAI-1) activity (-32.4% and -19.6%, respectively) and PAI-1 antigen (-9.9% and -7.8%, respectively). Intergroup analysis revealed reduction in both mean PAI-1 activities and PAI-1 antigen levels in the two treatment groups when compared with the control. Contrary to the standard estrogen plus dydrogesterone treatment, ultra-low dose HT revealed positive effects on hemostasis by intensifying fibrinolysis through a decrease in both PAI-1 activity and antigen levels, and with no impact on thrombin generation.

Re: "Plasminogen Activator Inhibitor-1 and Pericardial Fat in Individuals with Type 2 Diabetes Mellitus" by Bayomi et al. (Metab Syndr Relat Disord 2017;15:269-275).

Plasminogen activator inhibitor-1 (PAI-1) is a member of the serine protease inhibitor (serpin) superfamily, which inactivates tissue plasminogen activator (tPA); therefore, increased level of PAI-1 antigen counteracts the anticoagulant effect of tPA and facilitates the fibrin clot formation. Plasma PAI-1 antigen and activity levels are associated with increased body mass index and with features of the insulin resistance syndrome like obesity and diabetes. Visceral adipose tissue produces more PAI-1 than subcutaneous adipose tissue: This increased production of PAI-1 from the visceral adipose tissue is one important link between visceral obesity and cardiovascular disease. Besides visceral adipose tissue, there is mounting evidence that epicardial adipose tissue may be an important source of PAI-1, especially in patients with type 2 diabetes.

Plasma levels of plasminogen activator inhibitor-1 and bleeding phenotype in patients with von Willebrand disease.

von Willebrand disease (VWD) is the most common inherited bleeding disorder. In VWD patients, large variations in bleeding tendency are observed, which cannot be completely explained by the variation in von Willebrand factor levels or activities. Thus, there must be additional factors, for instance, changes in fibrinolysis that have an effect on the variation in bleeding tendency in VWD patients. To investigate whether plasminogen activator inhibitor-1 (PAI-1) level influences the variation in bleeding tendency in VWD patients. PAI-1 antigen levels were measured in the plasma of 633 patients with moderate or severe VWD who participated in the 'Willebrand in the Netherlands' (WiN) study, a nationwide multicentre cross-sectional study. Bleeding severity was assessed using the Tosetto bleeding score. PAI-1 levels increased with age (Spearman's rho: 0.225, P<0.001) and were higher in men (23 [IQR 12-60] vs. 20 [IQR 10-44]ngmL-1 in women, P=0.039), whereas the bleeding score was higher in women (11 [IQR 7-17] vs. 9 [IQR 5-14] ngmL-1 in men, P=0.002). After adjustment for age and sex by stratification, PAI-1 level and bleeding score were negatively correlated (Spearman's rho: -0.170, P=0.017) in the group of 196 young (age≤45year) female VWD patients, accounting for 31% of our study population. In young female VWD patients, we observed that low PAI-1 levels were associated with a higher bleeding score, which may partly explain the observed variability in bleeding phenotype in VWD patients.

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays.

Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g), platelet-containing (352 g) and platelet-rich plasma (200 g) were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation). Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin) showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly through release of latent plasminogen activator inhibitor-1 with limited effects on plasminogen activator inhibitor-1 activity, tissue plasminogen activator/plasminogen activator inhibitor-1 complex or plasma clot lysis time. Platelets may however also have functional effects on plasma fibrinolytic potential in the presence of high platelet counts, such as in platelet-rich plasma.

Impaired fibrinolysis in angiographically documented coronary artery disease.

Impaired fibrinolysis may predispose to coronary artery disease (CAD). Hypofibrinolysis due to high levels of plasminogen activator inhibitor-1 (PAI-1) has been reported in CAD. A novel regulator of fibrinolytic activity, thrombin activatable fibrinolysis inhibitor (TAFI), has attracted attention in recent years. It acts by blocking the formation of a ternary complex of plasminogen, fibrin, and tissue plasminogen activator (t-PA). Previously ambiguous results regarding TAFI levels have been reported in CAD. We measured plasma levels of PAI-1 and TAFI antigen in 123 patients with age ranging from 40 to 65 years who had been submitted to coronary angiography and assessed the association of these markers with the extent of stenosis in three groups: angiographically normal artery (NAn), mild to moderate atheromatosis (MA), and severe atheromatosis (SA). Plasma levels of PAI-1 were increased in patients with severe atheromatosis compared to mild/moderate atheromatosis or to normal patients (66.60, 40.50, and 34.90 ng/mL, resp.; P < 0.001). For TAFI no difference was found between different groups. When patients were grouped in only two groups based on clinical cut-off point for intervention (stenosis less than or above 70%) we found increased plasma levels for PAI-1 (37.55 and 66.60 ng/mL, resp.; P < 0.001) and decreased plasma levels for TAFI (5.20 and 4.53 μg/mL, resp.; P = 0.04) in patients with stenosis above 70%. No difference was found in PAI-1 or TAFI levels comparing the number of affected vessels. Conclusion. As evidenced by a raised level of PAI-1 antigen, one can suggest an impaired fibrinolysis in stable CAD, although no correlation with the number of affected vessels was found. Curiously, a decreased plasma level of total TAFI levels was observed in patients with stenosis above 70%. Further studies measuring functional TAFI are required in order to elucidate its association with the extent of degree of atheromatosis.

Prognostic impact of urokinase-type plasminogen activator system components in clear cell renal cell carcinoma patients without distant metastasis.

BackgroundMembers of the urokinase-type plasminogen activator (uPA) system including uPA, its receptor uPAR and the plasminogen activator inhibitor 1 (PAI-1) play an important role in tumour invasion and progression in a variety of tumour types. Since the majority of clear cell renal cell carcinoma (ccRCC) shows distant metastasis at time of diagnosis or later, the interplay of uPA, uPAR and PAI-1 might be of importance in this process determining the patients’ outcome.MethodsCorresponding pairs of malignant and non-malignant renal tissue specimens were obtained from 112 ccRCC patients without distant metastasis who underwent tumour nephrectomy. Tissue extracts prepared from fresh-frozen tissue samples by detergent extraction were used for the determination of antigen levels of uPA, uPAR and PAI-1 by ELISA. Antigen levels were normalised to protein concentrations and expressed as ng per mg of total protein.ResultsAntigen levels of uPA, uPAR, and PAI-1 correlated with each other in the malignant tissue specimens (rs=0.51-0.65; all P<0.001). Antigen levels of uPA system components were significantly higher in tissue extracts of non-organ confined tumours (pT3+4) compared to organ-confined tumours (pT1+2; all P<0.05). Significantly elevated levels of uPAR and PAI-1 were also observed in high grade ccRCC. When using median antigen levels as cut-off points, all three uPA system factors were significant predictors for disease-specific survival (DSS) in univariate Cox’s regression analyses. High levels of uPA and uPAR remained independent predictors for DSS with HR=2.86 (95% CI 1.07-7.67, P=0.037) and HR=4.70 (95% CI 1.51-14.6, P=0.008), respectively, in multivariate Cox’s regression analyses. A combination of high antigen levels of uPA and/or uPAR further improved the prediction of DSS in multivariate analysis (HR=14.5, 95% CI 1.88-111.1, P=0.010). Moreover, high uPA and/or uPAR levels defined a patient subgroup of high risk for tumour-related death in ccRCC patients with organ-confined disease (pT1+2) (HR=9.83, 95% CI 1.21-79.6, P=0.032).ConclusionsHigh levels of uPA and uPAR in tumour tissue extracts are associated with a significantly shorter DSS of ccRCC patients without distant metastases.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2407-14-974) contains supplementary material, which is available to authorized users.

Abstract T P75: Temporal Profiles of Plasminogen Activator Inhibitor-1 Concentration and Activity Changes in Circulation after Focal Stroke and Tissue Type Plasminogen Activator Administration in Rats

Aims: Plasminogen activator inhibitor-1 (PAI-1) is the main and potent endogenous tissue-type plasminogen activator (tPA) inhibitor, but an important question on whether PAI-1 in blood stream responds and interferes with the exogenously administered tPA remains unexplored. We for the first time investigated temporal profiles of PAI-1 concentration and activity in circulation after stroke and tPA administration in rats. Methods: Permanent MCAO focal stroke of rats were treated with saline or 10mg/kg tPA at 3 hours after stroke (n=10 per group). Plasma (platelet free) PAI-1 antigen and activity levels were measured by ELISA at before stroke, 3, 4.5 (1.5 hours after saline or tPA treatments) and 24 hours after stroke. Since vascular endothelial cells and platelets are two major cellular sources for PAI-1 in circulation, we measured releases of PAI-1 from cultured endothelial cells and isolated platelets after direct tPA (4 μg/ml) exposures for 60 min in vitro by ELISA (n=4 per group). Results: At 3 hours after stroke, both plasma PAI-1 antigen and activity were significantly increased (3.09±0.67, and 3.42±0.57 fold of before stroke baseline, respectively, all data are expressed as mean±SE). At 4.5 hours after stroke, intravenous tPA administration significantly further elevated PAI-1 antigen levels (5.26±1.24), while as expected that tPA neutralized most elevated PAI-1 activity (0.33±0.05). At 24 hours after stroke, PAI-1 antigen levels returned to the before baseline level, however, there was a significantly higher PAI-1 activity (2.51±0.53) in tPA treated rats. In vitro tPA exposures significantly increased PAI-1 releases into culture medium in cultured endothelial cells (1.65±0.08) and platelets (2.02±0.17). Conclution: Our experimental results suggest that tPA administration may further elevate stroke-increased blood PAI-1 concentration, but also increase PAI-1 activity at late 24 hours after stroke. The increased PAI-1 releases after tPA exposures in vitro suggest tPA may directly stimulate PAI-1 secretions from vascular walls and circulation platelets, which partially contributes to the PAI-1 elevation observed in focal stroke rats. The underlying regulation mechanisms and pathological consequence need further investigation.

Circadian Variability of Fibrinolytic Markers and Endothelial Function in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is strongly associated with cardiovascular disease, including stroke and acute coronary syndromes. Plasminogen activator inhibitor-1 (PAI-1), the principal inhibitor of tissue-type plasminogen activator (t-PA), has a pronounced circadian rhythm and is elevated in both OSA and cardiovascular disease and may be an important link between the two conditions. Endothelial dysfunction is one of the underlying pathophysiological mechanisms of cardiovascular disease, and may be altered in OSA. Our primary aim was to compare circadian variability of PAI-1 and t-PA in patients with OSA and normal controls by determining the amplitude (peak level) and mesor (rhythm adjusted mean) of PAI-1 and t-PA in serial blood samples over a 24-h period. The secondary aim was to measure markers of endothelial function (brachial and radial artery flow) in patients with OSA compared with normal controls. Cross-sectional cohort study. Subjects age 18 y or older, with a body mass index of 25-45 kg/m(2), with or without evidence of untreated OSA. Plasma samples were collected every 2 h, in OSA patients and matched controls, over a 24-h period. PAI-1 and t-PA antigen and activity were measured. The presence or absence of OSA (apnea-hypopnea index of 5 or greater) was confirmed by overnight polysomnography. Endothelial function was measured via brachial artery flow mediated vasodilatation and computerized arterial pulse waveform analysis. The rhythm-adjusted mean levels of PAI-1 antigen levels in the OSA group (21.8 ng/mL, 95% confidence level [CI], 18 to 25.7) were significantly higher as compared to the non-OSA group (16 ng/mL, 95% CI, 12.2 to 19.8; P = 0.03). The rhythm-adjusted mean levels of PAI-1 activity levels in the OSA group (23.9 IU/mL, 95% CI, 21.4 to 26.5) were also significantly higher than in the non-OSA group (17.2 IU/ mL, 95% CI, 14.6 to 19.9; P < 0.001).There were strong correlations between amplitude of PAI-1 activity and severity of OSA as measured by AHI (P = 0.02), and minimum oxygen levels during sleep (P = 0.04). Endothelial function parameters did not differ significantly between the two groups. The presence of obstructive sleep apnea adversely affects circadian fibrinolytic balance with higher mean plasminogen activator inhibitor-1 activity and antigen, and significantly lower mean tissue-type plasminogen activator activity compared with controls. This perturbation may be an important mechanism for increased cardiovascular events in patients with obstructive sleep apnea. Intermittent hypoxia and changes in circadian clock gene activity in obstructive sleep apnea may be responsible for these findings and warrant further study. Favorable changes in fibrinolytic balance may underlie the reduction in cardiovascular events observed with the treatment of obstructive sleep apnea.

Coagulation disorders and aortic stenosis: a chicken and egg question?

Coagulation disorders and aortic stenosis: a chicken and egg question?

Deregulated expression of urokinase and its inhibitor type 1 in prostate cancer cells: Role of epigenetic mechanisms

Plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator (uPA) play a crucial role in cancer progression. In the present study we examined the regulation of PAI-1 and uPA expressions in normal prostate epithelial cells (PrEC) and the prostate cancer cell lines LNCaP, DU-145, and PC-3. The antigen and mRNA levels of PAI-1 were down-regulated in cancer cells, especially in LNCaP and DU-145. In the presence of proinflammatory cytokines, an increase of PAI-1 mRNA levels was observed in PrEC, LNCaP and PC-3, but not in DU-145 cells. Treatment with demethylating agent, 5-aza-2′-deoxycytidine increased the level of PAI-1 transcript in DU-145 cells and restored the inducing effect of cytokines on PAI-1 expression. An aberrant methylation of PAI-1 promoter in DU-145 and LNCaP cells was shown by methylation-sensitive high resolution melting (MS-HRM) analysis. PAI-1 methylation was also significantly increased in tumor samples (23.2±1.7%) in comparison to adjacent non-tumor tissue (6.0±0.8%). Furthermore, the expression of uPA was increased in high invasive cell lines DU-145 and PC-3 in comparison to PrEC and low invasive LNCaP cells. MS-HRM analysis revealed aberrant methylation of uPA promoter in LNCaP cells, but not in PrEC, DU-145 and PC-3 cells, as well as in normal and prostate cancer tissue samples. In conclusion, the study shows that PAI-1 and uPA expressions were changed in opposite directions in high invasive prostate cancer cell lines resulting in a strong decrease of PAI-1/uPA ratio, which may indicate a shift towards proteolytic activities. Methylation of the PAI-1 gene is suggested as one of the molecular mechanisms involved in the cancer-associated down-regulation of the PAI-1 expression.

Early Insulin Glycemic Control Combined With tPA Thrombolysis Reduces Acute Brain Tissue Damages in a Focal Embolic Stroke Model of Diabetic Rats

Therapeutic effects of early insulin glycemic control for poststroke hyperglycemia in combination with tissue-type plasminogen activator (tPA) thrombolytic therapy have not yet been studied but are of great clinical interest. In this study, we tested the effects of insulin plus tPA combination in a model of focal embolic stroke in Type I diabetic rats. Streptozotocin was used to produce Type I diabetes in male Wistar rats for 6 weeks and then embolic focal strokes were induced. All rats were treated with insulin or saline at 1 hour followed by tPA or saline at 1.5 hour after stroke. Mortality, infarction, hemispheric swelling, hemorrhagic transformation, and perfusion defects were examined at 24 hours after stroke. Total plasma plasminogen activator inhibitor-1 antigen and activity levels were measured before stroke and 1.5, 3, and 6 hours after stroke by ELISA. Early insulin glycemic control alone or tPA thrombolysis alone had no significant effects on ischemic infarction. However, early insulin glycemic control combined with tPA significantly reduced brain infarction and swelling, ameliorated tPA-associated hemorrhagic transformation, and improved plasma perfusion at 24 hours after stroke. We also found that the combination significantly decreased plasma plasminogen activator inhibitor-1 antigen level at 6 hours and plasminogen activator inhibitor-1 activity at 1.5 and 6 hours after stroke. Early insulin glycemic control may be beneficial in combination with tPA thrombolysis for ischemic stroke with diabetes mellitus or poststroke hyperglycemia.