Plasminogen Activator Inhibitor-1 Antigen Research Articles

Prothrombotic plasma fibrin clot phenotype is associated with spontaneous echo contrast in atrial fibrillation: The role of protein carbonylation

IntroductionSpontaneous echo contrast (SEC) and left atrial appendage thrombus (LAAT) increase the risk of stroke and its severity in patients with atrial fibrillation (AF). Formation of denser fibrin networks and impaired fibrinolysis are associated with stroke risk in AF. This study investigated whether the prothrombotic fibrin clot phenotype characterizes patients with SEC/LAAT. MethodsWe studied 139 anticoagulated patients with AF (median age, 70 years), who underwent transesophageal echocardiography (TEE). SEC and LAAT were recorded. We assessed plasma fibrin clot properties, i.e. permeability (Ks) and clot lysis time (CLT), von Willebrand Factor (vWF) antigen, endogenous thrombin potential (ETP), proteins involved in thrombosis and fibrinolysis, as well as plasma carbonylated protein content (PC). ResultsSEC/LAAT was identified in 36 subjects (25.9 %) and was associated with heart failure (HF), AF duration, higher CHA2DS2VASc score, N-terminal prohormone of brain natriuretic peptide, and growth differentiation factor 15. Patients with SEC/LAAT had lower Ks (−15 %) and prolonged CLT (+19 %), along with higher fibrinogen (+24 %), ETP (+3 %), and plasminogen activator inhibitor-1 antigen (+16 %) compared with the remainder. Thrombin-activatable fibrinolysis inhibitor antigen, plasminogen, α2 − antiplasmin, and tissue plasminogen activator antigen were similar between the two groups. PC content was 50 % higher in SEC/LAAT and correlated with Ks (r = −0.47, p < 0.001) and CLT (r = 0.40, p < 0.001). On multivariate analysis, Ks, CLT, and PC levels, along with HF, remained independently associated with SEC/LAAT. ConclusionsWe demonstrated a formation of denser and poorly lysable fibrin networks in AF patients with SEC/LAAT despite anticoagulation. We suggest that this phenomenon is in part related to enhanced oxidative stress.

Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 complex as a serum biomarker for COVID-19.

Patients with coronavirus disease-2019 (COVID-19) have an increased risk of thrombosis and acute respiratory distress syndrome (ARDS). Thrombosis is often attributed to increases in plasminogen activator inhibitor-1 (PAI-1) and a shut-down of fibrinolysis (blood clot dissolution). Decreased urokinase-type plasminogen activator (uPA), a protease necessary for cell-associated plasmin generation, and increased tissue-type plasminogen activator (tPA) and PAI-1 levels have been reported in COVID-19 patients. Because these factors can occur in free and complexed forms with differences in their biological functions, we examined the predictive impact of uPA, tPA, and PAI-1 in their free forms and complexes as a biomarker for COVID-19 severity and the development of ARDS. In this retrospective study of 69 Japanese adults hospitalized with COVID-19 and 20 healthy donors, we found elevated free, non-complexed PAI-1 antigen, low circulating uPA, and uPA/PAI-1 but not tPA/PAI-1 complex levels to be associated with COVID-19 severity and ARDS development. This biomarker profile was typical for patients in the complicated phase. Lack of PAI-1 activity in circulation despite free, non-complexed PAI-1 protein and plasmin/α2anti-plasmin complex correlated with suPAR and sVCAM levels, markers indicating endothelial dysfunction. Furthermore, uPA/PAI-1 complex levels positively correlated with TNFα, a cytokine reported to trigger inflammatory cell death and tissue damage. Those levels also positively correlated with lymphopenia and the pro-inflammatory factors interleukin1β (IL1β), IL6, and C-reactive protein, markers associated with the anti-viral inflammatory response. These findings argue for using uPA and uPA/PAI-1 as novel biomarkers to detect patients at risk of developing severe COVID-19, including ARDS.

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.

Development of a Hypercoagulable-Hypofibrinolytic State Early After Spinal Cord Injury

ObjectivesTo determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes. DesignCross-sectional study. SettingNeurorehabilitation hospital and general community. ParticipantsThirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk). InterventionsNot applicable. Main Outcome MeasuresCirculating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay. ResultsThirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults. ConclusionsSubacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI.

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.

Plasma levels of fibrinolytic and coagulation biomarkers in HIV-infected individuals on highly active antiretroviral therapy: A case-control study in a Northern Ghanaian population.

Impaired coagulation and fibrinolysis have been implicated in thromboembolism in human immunodeficiency virus (HIV)-infected individuals. This study evaluated the plasma levels of plasminogen activator inhibitor-1 (PAI-1) and coagulation biomarkers in HIV-infected individuals on highly active antiretroviral therapy (HAART). This matched case-control study from March to December, 2020 comprised 76 participants: 38 HIV-positive individuals on HAART and 38 apparently healthy HIV-negative individuals as controls. Blood samples were collected for prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimers, PAI-1, and soluble fibrin monomer complex (SFMC) estimations. The data were analysed using SPSS version 22.0 and statistical significance was set at p < 0.05. Activated partial thromboplastin time was significantly lower in HIV seropositive individuals on HAART compared with HIV seronegative controls (25.90 s vs. 29.0 s, p = 0.030); however, PT, SFMC, D-dimers, and PAI-1 were significantly higher among the HIV-seropositive individuals compared with the controls: PT: (16.29 s ± 2.16 vs. 15.15 s ± 2.60, p = 0.010), SFMC: [8.53 ng/mL (8.03-9.12) vs. 7.84 ng/mL (7.32-8.58), p = 0.005]), D-Dimer: [463.37 ng/mL (402.70-526.33) vs. 421.11 ng/mL (341.11-462.52), p = 0.015], and PAI-1: [12.77 ng/mL (10.63-14.65) vs. 11.27 ng/mL (10.08-12.95), p = 0.039]. PAI-1 showed a moderate positive correlation with D-Dimer (r = 0.659, p < 0.001) and SFMC (r = 0.463, p = 0.003) among HIV-positive individuals on HAART. There was a strong positive correlation between the plasma PAI-1 concentration and the HIV viral load (r = 0.955, p < 0.001). HIV-seropositive individuals on HAART have deranged coagulation and fibrinolytic markers. Higher HIV viral load correlates strongly with elevated plasma levels of PAI-1 antigens. Periodic assessment of markers of coagulation and fibrinolysis be included in the management of HIV/AIDS in Ghana.

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.

Hypercoagulability State Combined with Post-Treatment Hypofibrinolysis in Invasive Breast Cancer: A Seven-Year Follow-Up Evaluating Disease-Free and Overall Survival.

(1) Background: Cancer treatment, including chemotherapy, endocrine therapy, targeted therapy and radiotherapy, has been identified as an important independent risk factor for venous thromboembolism in cancer patients. The aim of the study was to evaluate the effect of adjuvant therapy on the coagulation and fibrinolysis components in invasive breast cancer. (2) Methods: Tissue factor pathway inhibitor (TFPI), tissue factor (TF), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) antigen (concentration) and TFPI and TF activities were examined in the blood samples of 60 breast cancer patients treated by adjuvant chemotherapy, endocrine therapy, radiotherapy and immunotherapy. Blood samples were taken 24 h before primary surgery and 8 months after tumour removal surgery. (3) Results: Adjuvant therapy administrated to breast cancer patients significantly increased the concentration of plasma TF, the PAI-1 antigen and also the activity of TFPI and TF, but significantly decreased the level of the t-PA antigen. Combined chemotherapy and endocrine therapy, but not monotherapy, has an important effect on haemostatic biomarker levels. (4) Conclusions: Breast cancer patients receiving adjuvant therapy have an elevated risk of developing a hypercoagulability and hypofibrinolysis state leading to venous thromboembolism.

Renal transplant and hemostasis: early postoperative changes in recipients and donors

BackgroundThe benefit of administering pharmacologic thromboprophylaxis following renal transplantation remains uncertain. ObjectivesTo compare hemostatic parameters before and after renal transplant surgery in both recipients and their donors at predetermined time points. MethodsBlood samples were collected at baseline (T1), immediately after surgery (T2), and at 24 hours after surgery (T3) in both recipients and donors and at 72 (T4) and 120 hours (T5) from recipients only. Assays included in vitro thrombin generation, factor VIII (FVIIIc) activity, von Willebrand factor (VWF) antigen, D-dimer, antithrombin activity, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complexes, and plasminogen activator inhibitor-1 (PAI-1) antigen. ResultsFifty-two patients (28 recipients and 24 donors) were enrolled. Both donors and recipients had increased FVIIIc, VWF, F1 + 2, D-dimer, and PAI immediately after surgery but reduced antithrombin. Mixed-model analysis showed that the magnitude of change over time (between T1 and T3) for FVIIIc (mean estimated difference [MED], 72; 95% CI, 41-102; P < .0001), VWF (MED, 89; 95% CI, 35-142; P = .001), F1 + 2 (MED, 283; 95% CI, 144-422; P < .0001), thrombin-antithrombin complexes (MED, 3.5; 95% CI, 1.9-5.1; P < .0001), D-dimer (MED, 2.2; 95% CI, 1.0-3.3; P < .0001), PAI-1 (MED, 9.2; 95% CI, 3.4-14.9; P = .002), and time to peak thrombin generation (MED, 1.5; 95% CI, 0.35-2.7; P = .01) was more significant in recipients than in donors. ConclusionPersistence of a hypercoagulable state was more prominent in recipients after 24 hours despite recovery in renal function and initiation of thromboprophylaxis.

Characterization of the endotheliopathy, innate-immune activation and hemostatic imbalance underlying CAR-T cell toxicities: laboratory tools for an early and differential diagnosis

BackgroundChimeric antigen receptor (CAR)-T cell-based immunotherapy constitutes a revolutionary advance for treatment of relapsed/refractory hematological malignancies. Nevertheless, cytokine release and immune effector cell-associated neurotoxicity syndromes are life-threatening toxicities in which...

Amplified Thrombo-Inflammatory Biomarkers in Pulmonary Embolism with Augmented Responses in Von-Willebrand Factor, Microparticles and Interleukin-6 in Patients with Cancer

Introduction: The multifactorial and complex pathophysiology of pulmonary embolism (PE) involves dysregulation of hemostatic system including fibrinolytic imbalance, endothelial compromise, and generation of thrombotic mediators, along with cellular defects and hemodynamic derangement. These pathophysiologic processes results in the generation of thrombo-inflammatory biomarkers reflecting the endogenous hemostatic imbalance. Cancer is prevalent in PE patients and is considered as an added risk factor for the adverse outcomes. Thrombo-inflammatory biomarker profiling provide means to risk stratify PE patients. This study aimed to profile several of these biomarkers in normal individuals and PE patients and further demonstrate their additional amplification in patients with cancer as a co-morbidity. Materials & Method: Four hundred male and female patients of 18 years or older age, were included through enrolment in conjunction with an IRB approved project by the pulmonary embolism response team (PERT) registry. Diagnosis of PE was confirmed by computed tomography (CT), angiography or ventilation perfusion imaging. Blood samples were drawn with in 24-72 hours of confirmed diagnosis of acute PE. Normal human plasma (NHP) samples were obtained from 50 healthy individuals including 25 male and 25 female and used for referencing purposes. All of the plasma samples were analyzed for D-Dimer, plasminogen activator inhibitor-1 (PAI-1) antigen, tissue-type plasminogen activator (tPA), activated thrombin-activatable fibrinolysis inhibitor (TAFI-a), von Willebrand factor (vWF), c-Reactive Protein (CRP) and interleukin-6 (IL-6) were measured by commercially available ELISA methods. Microparticles were measured by using a chromogenic functional method. Individual biomarkers were compared to normal plasma and further stratified on cancer status and PE severity. Results are presented as mean±SD and fold increase. For the degree of association, GraphPad Prism Software was used. Results: PE patients exhibited varying levels of upregulation of all of the individual biomarkers compared to normal's, D-Dimer (37.05-fold), PAI-1 antigen (3.95-fold), tPA (4.69-fold), TAFI (1.21-fold), vWF (1.89-fold), CRP (35.34-fold), IL-6 (21.62-fold), and microparticles (3.04-fold) increase in PE patients with reference to NHP. When the PE group stratified into cancer and non-cancer patients, most of the biomarkers except D-Dimer and microparticles showed varying degree of modest elevation in the cancer group (figure 1). vWF, IL6 and microparticles levels were found to be further amplified in PE group with cancer. Of these three biomarkers, only vWF remained amplified when stratified by PE severity in patients with cancer, however this change was only observed in the low-grade PE patients (table 1). The IL-6 levels showed increased trend in the low-grade and sub-massive patient group, however because of the wide scatter, it was not significant. Conclusion: These studies demonstrate that thrombo-inflammatory biomarkers are upregulated in PE patients. Furthermore, PE patients with cancer exhibit amplified responses for vWF, IL-6 and microparticles levels suggesting their role in mediating the pathogenesis involving endothelial, inflammatory and thrombogenic mechanisms. Among the biomarkers studied, vWF is central to thrombo-inflammatory process and is distinct in PE cohort with cancer, despite taking into account the lower PE severity. These studies suggest that selective biomarker profiling of thrombo-inflammatory biomarkers may be valuable in the risk stratification and therapeutic management of PE patients at large. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

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.

Dynamics of indicators of endothelial dysfunction in children with obesity

Introduction. Constitutionally exogenous obesity (CEO) belongs to a number of significant medical and social problems of the modern world, assumes epidemic proportions and leads among alimentary-dependent pathology in children. The aim of the work was to determine changes in indicators of endothelial dysfunction (ED) in children of different age with obesity of various severity. Materials and methods. One hundred twenty six children aged of 6 to 17 years were comprehensively examined, data on changes in the serum content of ED mediators in CEOs grade 1-3 were presented by quantitative determination of nitric oxide, endothelin-1, leptin, homocysteine, intercellular adhesion molecules and vascular cell adhesion-1, tissue-type plasminogen activator inhibitor antigen, Willebrand factor and his antigen. Results. The regularities of changes in the concentrations of these compounds in the blood depending on the age of patients and the degree of obesity, which reflect the functional state of the endothelial system and can serve as criteria for the severity of ED requiring adequate and timely correction in children, have been established. Conclusion. Indicators of endothelial dysfunction can serve as criteria for its severity, their detection will allow optimizing early diagnosis and determining the amount of timely therapy.

Biomarkers of endothelial dysfunction and outcomes in coronavirus disease 2019 (COVID-19) patients: A systematic review and meta-analysis.

BackgroundSeveral studies have reported that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can directly infect endothelial cells, and endothelial dysfunction is often found in severe cases of coronavirus disease 2019 (COVID-19). To better understand the prognostic values of endothelial dysfunction in COVID-19-associated coagulopathy, we conducted a systematic review and meta-analysis to assess biomarkers of endothelial cells in patients with COVID-19.MethodsA literature search was conducted on online databases for observational studies evaluating biomarkers of endothelial dysfunction and composite poor outcomes in COVID-19 patients.ResultsA total of 1187 patients from 17 studies were included in this analysis. The estimated pooled means for von Willebrand Factor (VWF) antigen levels in COVID-19 patients was higher compared to healthy control (306.42 [95% confidence interval (CI) 291.37–321.48], p < 0.001; I2:86%), with the highest VWF antigen levels was found in deceased COVID-19 patients (448.57 [95% CI 407.20–489.93], p < 0.001; I2:0%). Meta-analysis showed that higher plasma levels of VWF antigen, tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 antigen (PAI-1) antigen, and soluble thrombomodulin (sTM) were associated with composite poor outcome in COVID-19 patients ([standardized mean difference (SMD) 0.74 [0.33–1.16], p < 0.001; I2:80.4%], [SMD 0.55 [0.19–0.92], p = 0.003; I2:6.4%], [SMD 0.33 [0.04–0.62], p = 0.025; I2:7.9%], and [SMD 0.55 [0.10–0.99], p = 0.015; I2:23.6%], respectively).ConclusionThe estimated pooled means show increased levels of VWF antigen in COVID-19 patients. Several biomarkers of endothelial dysfunction, including VFW antigen, t-PA, PAI-1, and sTM, are significantly associated with increased composite poor outcomes in patients with COVID-19.PROSPERO registration numberCRD42021228821

Regular Resistance Training Enhances Fibrinolytic Potential

Blood clots cause most cardiovascular events, such as heart attack and stroke. Blood markers of fibrinolysis, the capacity to dissolve blood clots, are independently associated with cardiovascular morbidity and mortality. Regular resistance training (RT) produces various muscular and vascular adaptations that are theorized to influence thrombotic potential, but there are no published longitudinal studies that examine fibrinolytic adaptations to RT. PURPOSE: The purpose of this study was to identify effects of an 8-week RT program on fibrinolytic potential. METHODS: Sixteen healthy adults (n = 12 women, 4 men; age = 23 ± 5 years) completed a RT program that targeted all major muscle groups, 3 times per week for 8 weeks. Exercises included 2-3 sets of 8-12 repetitions performed at approximately 60-80% of 1 RM. Body composition, circumferences, and 1 RM leg and chest press strength measures were obtained via standard methods. Resting blood samples were obtained by clean venipuncture at baseline and after 8 weeks of RT. Enzyme-linked immunosorbancy assays were used to assess plasma concentrations of the following fibrinolytic variables: active tissue plasminogen activator (tPA:c), tissue plasminogen activator antigen (tPA:g), active plasminogen activator inhibitor-1 (PAI-1:c), and plasminogen activator inhibitor-1 antigen (PAI-1:g). Statistical analyses were conducted using paired t-tests. RESULTS: Significant increases in lean mass (PRE = 52.18 ± 10.03, POST = 53.64 ± 10.42 kg), arm circumference (PRE = 29.89 ± 5.12, POST = 30.97 ± 4.92 cm), and mid-thigh circumference (PRE = 49.96 ± 5.43, POST = 51.08 ± 5.83 cm) were observed (all p<0.05). Maximal chest press (PRE = 57.8 ± 37.5, POST = 73.3 ± 43.2 kg) and leg press strength (PRE = 189.5 ± 95.8, POST = 256.7 ± 97.9 kg) significantly increased (p<0.01). PAI-1:c (PRE = 20.3 ± 32.5, POST = 9.5 ± 20.9 U/ml, p=0.05) and PAI-1:g decreased (PRE = 10.18 ± 8.98, POST = 7.20 ± 5.74 ng/dl, p<0.05 ). No change in tPA:c or tPA:g occurred. CONCLUSION: The decrease in plasma concentrations of total and active PAI-1 indicate reduced inhibition of fibrinolytic activation, suggesting that the risk of a cardiovascular event is reduced after resistance training. The mechanisms underlying this specific adaptation may relate to increased skeletal muscle mass, but additional research is warranted.

Elevated Lactate Levels in Acute Pulmonary Embolism Are Associated with Prothrombotic Fibrin Clot Properties: Contribution of NETs Formation.

Background: Elevated plasma lactate levels correlate with high mortality rate in acute pulmonary embolism (PE) patients. We hypothesized that elevated lactate levels correlate with prothrombotic fibrin clot properties and enhanced neutrophil extracellular trap (NET) formation in acute PE. Methods: As many as 126 normotensive acute PE patients (aged 58 ± 14 years) were enrolled. Plasma fibrin clot permeability (Ks), clot lysis time (CLT), endogenous thrombin potential (ETP), citrullinated histone H3 (citH3), and plasminogen activator inhibitor-1 antigen (PAI-1), together with plasma L-lactate levels were evaluated on admission. Results: Lactate levels ≥2 mM were found in 70 (55.6%) patients in whom we observed 29% higher neutrophil count and 45% elevated plasma citH3 levels. Elevated lactate levels were associated with more prothrombotic fibrin properties as reflected by 11% reduced Ks, 13% longer CLT, along with 11% increased ETP. Lactate levels were positively associated with plasma citH3 concentrations, ETP, CLT, and PAI-1 (p < 0.05). An increase of lactate levels by 1 mM leading to the prolongation of CLT by 8.82 min was shown in the linear regression. Conclusions: Our findings suggest a new mechanism contributing to a negative impact of elevated lactate levels on prognosis in acute PE patients, in particular hypofibrinolysis, associated with enhanced NET formation.

Functional plasminogen activator inhibitor 1 is retained on the activated platelet membrane following platelet activation.

Platelets harbor the primary reservoir of circulating plasminogen activator inhibitor 1 (PAI-1), but the reportedly low functional activity of this pool of inhibitor has led to debate over its contribution to thrombus stability. Here we analyze the fate of PAI-1 secreted from activated platelets and examine its role in maintaining thrombus integrity. Activation of platelets results in translocation of PAI-1 to the outer leaflet of the membrane, with maximal exposure in response to strong dual agonist stimulation. PAI-1 is found to co-localize in the 'cap' of phosphatidylserine-exposing platelets with its co-factor, vitronectin, and fibrinogen. Inclusion of tirofiban or Gly-Pro-Arg-Pro significantly attenuated exposure of PAI-1, indicating a crucial role for integrin αIIbβ3 and fibrin in delivery of PAI-1 to the activated membrane. Separation of platelets post stimulation into soluble and cellular components revealed the presence of PAI-1 antigen and activity in both fractions, with approximately 40% of total platelet-derived PAI-1 remaining associated with the cellular fraction. Using a variety of fibrinolytic models, we found that platelets produce a strong stabilizing effect against tissue plasminogen activator (tPA)-mediated clot lysis. Platelet lysate, as well as soluble and cellular fractions, stabilize thrombi against premature degradation in a PAI-1-dependent manner. Our data show for the first time that a functional pool of PAI-1 is anchored to the membrane of stimulated platelets and regulates local fibrinolysis. We reveal a key role for integrin αIIbβ3 and fibrin in delivery of PAI-1 from platelet α-granules to the activated membrane. These data suggest that targeting platelet-associated PAI-1 may represent a viable target for novel profibrinolytic agents.

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.