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The implications of altered coagulation-fibrinolytic system in the pathophysiology of several vascular disorders, such as stroke and myocardial infarction, have been well researched upon and established. However, its role in the progression of diabetic retinopathy has not been explored much. Since a decade, it is known that hyperglycemia is associated with a hypercoagulated state and the various impairments it causes are well acknowledged as independent risk factors for the development of cardiovascular diseases. But recent studies suggest that the hypercoagulative state and diminished fibrinolytic responses might also alter retinal homeostasis and induce several deleterious molecular changes in retinal cells which aggravate the already existing hyperglycemia-induced pathological conditions and thereby lead to the progression of diabetic retinopathy. The major mediators of coagulation-fibrinolytic system whose concentration or activity get altered during hyperglycemia include fibrinogen, antithrombin-III (AT-III), plasminogen activator inhibitor-1 (PAI-1) and von Willebrand factor (vWF). Inhibiting the pathways by which these altered mediators get involved in the pathophysiology of diabetic retinopathy can serve as potential targets for the development of an adjuvant novel alternative therapy for diabetic retinopathy., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Introduction: Elevated plasminogen activator inhibitor-1 (PAI-1) reduces fibrinolytic potential in plasma, contributing to thrombotic disease. Thus, inhibiting PAI-1 activity is clinically desirable. We recently demonstrated that tissue plasminogen activator (tPA) remains on the surface of vascular endothelial cells (VECs) after secretion in a heavy-chain dependent manner, which is essential for high fibrinolytic activity on the surface of VECs, and that PAI-1 dissociates retained tPA from the cell surface as a result of high-molecular weight complex formation. Based on the model whereby amounts of tPA and its equilibrium with PAI-1 dynamically change after exocytosis, we examined how TM5275, a newly synthesized small molecule PAI-1 inhibitor, modulated tPA retention and VEC surface-derived fibrinolytic activity using microscopic techniques., Materials and Methods: The effects of TM5275 on the kinetics of the secretion and retention of green fluorescent protein (GFP)-tagged tPA (tPA-GFP) on VECs were analyzed using total internal reflection fluorescence microscopy. The effects of TM5275 on the generation of plasmin activity were evaluated by both plasminogen accumulation and fibrin clot lysis on tPA-GFP-expressing VECs using confocal laser scanning microscopy., Results: TM5275 at concentrations of 20 and 100 μM significantly prolonged the retention of tPA-GFP on VECs by inhibiting tPA-GFP-PAI-1 high-molecular-weight complex formation. TM5275 enhanced the time-dependent accumulation of plasminogen as well as the dissolution of fibrin clots on and around the tPA-GFP-expressing cells., Conclusions: The profibrinolytic effects of TM5275 were clearly demonstrated by the prolongation of tPA retention and enhancement of plasmin generation on the VEC surface as a result of PAI-1 inhibition., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Upon cellular injury, damage-associated molecular patterns (DAMPs) are released into the extracellular space and evoke proinflammatory and prothrombotic responses in animal models of sterile inflammation. However, in clinical settings, the dynamics of DAMP levels after trauma and links between DAMPs and trauma-associated coagulopathy remain largely undetermined. Methods: Thirty-one patients with severe trauma, who were transferred to Kagoshima City Hospital between June 2018 and December 2019, were consecutively enrolled in this study. Blood samples were taken at the time of delivery, and 6 and 12 h after the injury, and once daily thereafter. The time-dependent changes of coagulation/fibrinolysis markers, including thrombin-antithrombin complex, α2-plasmin inhibitor (α2-PI), plasmin-α2-PI complex, and plasminogen activator inhibitor-1 (PAI-1), and DAMPs, including high mobility group box 1 and histone H3, were analyzed. The relationship between coagulation/fibrinolysis markers, DAMPs, Injury Severity Score, in-hospital death, and amount of blood transfusion were analyzed. Results: The activation of coagulation/fibrinolysis pathways was evident at the time of delivery. In contrast, PAI-1 levels remained low at the time of delivery, and then were elevated at 6–12 h after traumatic injury. Histone H3 and high mobility group box 1 levels were elevated at admission, and gradually subsided over time. PAI-1 levels at 6 h were associated with serum histone H3 levels at admission. Increased histone H3 levels and plasmin-α2-PI complex levels were associated with in-hospital mortality. α2-PI levels at admission showed the strongest negative correlation with the amount of blood transfusion. Conclusion: The elevation of histone H3 levels and fibrinolysis perturbation are associated with fatal outcomes in patients with traumatic injury. Patients with low α2-PI levels at admission tend to require blood transfusion. [ABSTRACT FROM AUTHOR]

Abstract Background The pathophysiological mechanisms of acute coagulopathy of trauma-shock (ACOTS) are reported to include activated protein C-mediated suppression of thrombin generation via the proteolytic inactivation of activated Factor V (FVa) and FVIIIa; an increased fibrinolysis via neutralization of plasminogen activator inhibitor-1 (PAI-1) by activated protein C. The aims of this study are to review the evidences for the role of activated protein C in thrombin generation and fibrinolysis and to validate the diagnosis of ACOTS based on the activated protein C dynamics. Methods We conducted systematic literature search (2007–2017) using PubMed, the Cochrane Database of Systematic Reviews (CDSR), and the Cochrane Central Register of Controlled Trials (CENTRAL). Clinical studies on trauma that measured activated protein C or the circulating levels of activated protein C-related coagulation and fibrinolysis markers were included in our study. Results Out of 7613 studies, 17 clinical studies met the inclusion criteria. The levels of activated protein C in ACOTS were inconsistently decreased, showed no change, or were increased in comparison to the control groups. Irrespective of the activated protein C levels, thrombin generation was always preserved or highly elevated. There was no report on the activated protein C-mediated neutralization of PAI-1 with increased fibrinolysis. No included studies used unified diagnostic criteria to diagnose ACOTS and those studies also used different terms to refer to the condition known as ACOTS. Conclusions None of the studies showed direct cause and effect relationships between activated protein C and the suppression of coagulation and increased fibrinolysis. No definitive diagnostic criteria or unified terminology have been established for ACOTS based on the activated protein C dynamics.

Abstract: Using patients with polycythemia vera (PV) as an experimental model, we evaluated the impact of clot retraction (CR) and architecture of the clot on fibrinolysis. We studied the kinetics of clot retraction and the fibrinolysis rate in whole blood from 48 PV patients and 48 healthy controls. Measurements were performed before and after isovolemic eryhrocytapheresis (ECP). CR was measured by optical method. Clot lysis time (CLT) and maximum clot firmness (MCF) were measured by thromboelastometry in recalcified blood supplemented with t-PA and tissue factor. Compared with healthy controls, CR rate in PV patients was higher (0.0219 vs. 0.0138; p<0.001), the clot volume smaller and MCF elevated (64 vs. 58mm). CR rate correlated with platelet count (r=0.546; p=0.001) but not with erythrocyte concentration (r=0.192; p>0.3). Compared with healthy controls, CLT in PV patients was significantly prolonged (158min vs. 71min). Fibrinolysis rate inversely correlated with CR rate (r=-0.566; p<0.001); MCF (r=-0.704; p<0.001) and platelet count (r=-0.461; p<0.001). As judged by confocal microscope, in comparison to healthy controls, clots formed in blood from PV patients demonstrated booth a distinctly higher degree of crosslinking and possessed thinner fibers. Altered CR, MCF and fibrinolysis speeds were not normalized following the ECP procedure. Tirofiban (a blocker of platelet GPIIb/IIIa receptors), unlike aspirin, normalized abnormal CR and fibrinolysis in blood from PV patients. Collectively, our data indicate that in PV patients, abnormal CR may result in formation of thrombi that are more resistant to fibrinolysis. ECP and aspirin failed to normalize platelet-related fibrinolysis resistance. [Copyright &y& Elsevier]

Abstract: Introduction: Renal transplant recipients are at increased risk of venous thromboembolic events, which is in part caused by their treatment with maintenance immunosuppressive drugs. Because we observed an increased incidence of venous thromboembolic events in renal transplant recipients treated with the mTOR inhibitor (mTORi) everolimus, we aimed to identify prothrombotic mechanisms of this immunosuppressive drug. Materials and Methods: In a single center study, nested in a multi-center randomized controlled trial, we measured parameters of coagulation, anti-coagulation and fibrinolysis in renal transplant recipients, receiving the mTORi everolimus (n=16, mTOR group) and compared them to a similar patient group, receiving a calcineurin inhibitor and/or mycophenolate sodium (n=20, non-mTOR group). All patients were at least 6months following transplantation with a stable transplant function. Results: The use of an mTORi was associated with significantly higher levels of von Willebrand factor, prothrombin fragment 1+2, thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 as compared to a non-mTORi based immunosuppressive regimen. Conclusions: Treatment with an mTORi leads to increased endothelial activation, thrombin formation and impaired fibrinolysis in renal transplant recipients. This suggests an increased risk of thrombotic events in renal transplant recipients treated with mTOR inhibitors. A prospective study to establish the precise risk of thrombotic events in these patients is urgently needed. [Copyright &y& Elsevier]

Abstract: Introduction: Patients with stable coronary artery disease (CAD) are at risk of arterial thrombosis causing myocardial infarction. Detection of global haemostatic markers of hypercoagulability and hypofibrinolysis may be important for risk stratification and individualised treatment. We examined overall haemostatic potential (OHP) and thrombin generation in a group of stable CAD patients. We also sought to investigate associations between fibrinolytic inhibitors and abnormal global fibrinolysis in these patients. Materials and Methods: Blood samples were collected from 56 patients defined by coronary anatomy as symptomatically stable CAD. Medications were recorded. Samples were analysed using the global coagulation assays OHP and thrombin generation (calibrated automated thrombogram, CAT), platelet aggregometry measured by Multiplate®, and levels of plasminogen activator inhibitor-1 (PAI-1) antigen measured by ELISA. Results were compared with a reference group of healthy controls. Results: Stable CAD patients displayed increased fibrin and thrombin generation and impaired fibrinolysis (decreased overall fibrinolytic potential, OFP, and increased clot lysis time) compared with healthy controls. No effect of antiplatelet agents or other medications on these parameters was observed using platelet-poor plasma. After multivariate adjustment, OFP of healthy individuals was significantly associated with fibrinogen, but in CAD patients PAI-1 became an important determinant. Conclusions: Hypercoagulability of plasma is observed in stable CAD, with both increased thrombin generation and reduced fibrinolytic potential making a significant contribution. The OHP assay may provide a simple method of identifying hypercoagulability in individual patients. [Copyright &y& Elsevier]

Abstract: Plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism may have significance for PAI-1 expression. High levels of PAI-1 in endometrial cancer patients are associated with a poor prognosis. The objective of this study was to evaluate the PAI-1 4G/5G polymorphism in women with and without endometrial cancer and to analyze the influence of this polymorphism on PAI-1 expression in endometrial tissue. In 423 women (212 patients with endometrial cancer and 211 controls) PAI-1 4G/5G polymorphism was determined by PCR amplification using allele-specific primers. Quantitative real-time RT-PCR assay was used to quantify PAI-1 mRNA and PAI-1 protein levels were quantified by ELISA in tissue extracts from 33 patients with endometrial cancer and from 70 endometrial tissues from control women. The frequency of PAI-1 4G/4G genotype (P =0.010) and the PAI-1 4G allele (P =0.009) was significantly higher in patients than in controls. The frequency of PAI-1 4G allele was significantly higher in patients with stage IB than in those with stage IA (P =0.03). Control women with the 4G/4G genotype had higher endometrial PAI-1 protein (P =0.018) and mRNA (P =0.004) levels than those with the 5G/5G genotype. A significant increase in PAI-1 protein and mRNA was observed in endometrial cancer tissue in comparison with the endometrial tissue from control women (P <0.01). In conclusion, frequencies of the PAI-1 4G allele and 4G/4G genotype were found significantly more often in women with endometrial cancer than in controls. PAI-1 levels in endometrial tissue seem to be associated with PAI-1 4G/5G polymorphism. These findings suggest that the PAI-1 4G/4G genotype may be associated with the risk of endometrial cancer in a Caucasian population. Further studies with a larger number of patients are needed to clarify the influence of this PAI-1 polymorphism in endometrial cancer. [Copyright &y& Elsevier]

Abstract: Introduction: Endometriosis is a benign gynecologic disease with a high prevalence. It is a multifactorial and polygenic entity in which the fibrinolytic system may be implicated. The objective of this study was to evaluate the plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism in a group of women with and without endometriosis and to analyze the influence of this polymorphism in PAI-1 expression in endometrial tissue and peritoneal fluid. Material and methods: In 389 women (170 patients with endometriosis and 219 controls) PAI-1 4G/5G polymorphism was determined by PCR amplification using allele–specific primers. Quantitative real–time RT-PCR assay was used to quantify PAI-1 mRNA and PAI-1 antigen (ag) levels were quantified by ELISA. Results: The genotype and allele frequencies of PAI-1 4G/5G polymorphism did not differ significantly between patients and controls. Control women with the 4G/4G genotype had higher endometrial PAI-1ag (P =0.026) and mRNA (P =0.014) levels than those with the 5G/5G genotype. Control carrying the 4G/4G genotype tended to have higher peritoneal fluid PAI-1ag levels than those carrying the 5G/5G genotype. Moreover, PAI-1ag levels in peritoneal fluid were higher in patients than in controls (P=0.003). Conclusions: The PAI-1 genotype distribution was similar in patients and controls. PAI-1 levels in endometrial tissue and peritoneal fluid seem to be associated with PAI-1 4G/5G polymorphism in controls. The increased PAI-1ag levels observed in peritoneal fluid from patients could contribute to increase the peritoneal adhesions observed in endometriosis. [Copyright &y& Elsevier]

Abstract: Proteolysis in general and specifically the plasminogen activating system regulated by urokinase (uPA) its specific receptor, the GPI membrane anchored urokinase receptor (uPAR) and the specific plasminogen activator inhibitor 1 (PAI-1) plays a major role in tumorigenesis, tumor progression, tumor invasion and metastasis formation. This is exemplified by a body of published work showing a positive correlation between the expression of uPA or uPAR in several tumors and their malignancy. It is generally assumed that such a “pro-malignant” effect of the uPA–uPAR system is mediated by increased local proteolysis thus favoring tumor invasion, by a pro-angiogenic effect of this system and also by uPA–uPAR signaling towards the tumor thereby shifting the tumor phenotype to a more “malignant” one. However, when tumor patients are analyzed for long term survival, those with high levels of the inhibitor of the system, PAI-1 have a much worse prognosis than those with lower PAI-1 levels. This indicates that increased overall proteolysis alone cannot be made responsible for the adverse effects of the plasminogen activating system in tumors. Moreover, it becomes increasingly evident that components of the fibrinolytic system secreted by the tumor cells themselves are not solely responsible for a correlation between the plasminogen activating system and tumor malignancy; components of the plasminogen activating system secreted by stroma cells or cells of the immune system such as macrophages contribute also to the impact of fibrinolysis on malignancy. This review summarizes the evidence for the role of plasminogen activator inhibitor-1 in mediating the malignant phenotype and possible mechanism thereby trying to explain the “PAI-1 paradox in cancer” on a molecular level. [Copyright &y& Elsevier]

It has been previously shown that essential hypertension (EH) is associated with coagulation–fibrinolytic balance disorders. Our study was conducted in order to investigate disturbances in coagulation–fibrinolysis in offsprings of hypertensive parents. Two groups were studied: 44 healthy normotensive individuals (17 male, 27 female, age range 12–22 years) with a documented family history of hypertension and 33 individuals (14 male, 19 female, age range 11–21 years) without a family history of essential hypertension. The following parameters were determined in both groups: plasminogen activator inhibitor-1 antigen, tissue plasminogen activator antigen, fibrinogen, fibrin degradation products, thrombomodulin, protein S antigen, protein C activity, von Willebrand factor Ag, factor VII and factor XII activity. Additionally, systolic and diastolic blood pressure, insulin levels, blood lipids and heart rate were determined. The two groups were not found to have differences with respect to age, gender, body mass index, blood lipids and insulin levels. Hypertensive offsprings had significantly higher plasma levels of plasminogen activator inhibitor-1 antigen, fibrinogen, fibrin degradation products, protein S antigen and factor XII activity, while no differences were observed to the other haemostatic variables studied. Hence, offsprings of hypertensives had significantly higher diastolic blood pressure and heart rate. In conclusion, alterations regarding blood pressure, heart rate and fibrinolytic function exist in offsprings of hypertensive parents compared to individuals without family history of hypertension. [Copyright &y& Elsevier]

The concentrations in blood of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of fibrinolysis and proteolysis, are elevated in obese and insulin-resistant subjects, predispose them to the risk of thrombosis, and may accelerate atherogenesis. Adipose tissue is a prominent source. Accordingly, intracellular signaling pathways that may influence PAI-1 expression in adipocytes have been the focus of considerable study. Rho, a small GTP binding and GTPase protein, when activated in turn activates its target, Rho-associated coiled-coil forming protein, to yield an active kinase, Rho-kinase, an effector in the Rho pathway. Rho-kinase exerts calcium-sensitizing effects in vascular smooth muscle cells and inhibitory effects on transforming growth factor-β (TGF-β) expression in chicken embryonic heart cells. Because TGF-β is a powerful agonist of PAI-1 expression, we characterized the effects of inhibition of Rho-kinase in 3T3-L1 adipocytes. PAI-1 mRNA was determined by Northern blotting, and PAI-1 protein was determined by Western blotting. The Rho-kinase inhibitor, Y-27632 [(R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide], increased PAI-1 expression markedly. Although genistein, a flavonoid tyrosine kinase, attenuated the increase of PAI-1 induced by Y-27632, other non-flavonoid tyrosine kinase inhibitors did not. However, another flavonoid, daidzein, which lacks tyrosine kinase activity, decreased basal PAI-1 expression and attenuated the induction of PAI-1 expression by Y-27632. Thus, the Rho/Rho-kinase system inhibits PAI-1 expression by a flavonoid-sensitive mechanism in adipocytes. Therefore, flavonoids may be useful in decreasing elevated PAI-1 expression in adipose tissue and its consequent pathophysiologic sequelae. [Copyright &y& Elsevier]

Plasminogen activator inhibitor-1 (PAI-1) is the major physiologic inhibitor of plasminogen activation in plasma and in the blood vessel wall. PAI-1 exhibits distinctive structural and functional properties that have been extensively studied over the past decade. Aside from the physiological role of PAI-1, there is accumulating evidence that increased production of PAI-1 may contribute to the development of ischemic cardiovascular disease. Efforts are now underway to develop and test specific inhibitors of PAI-1. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Post-cardiac arrest syndrome (PCAS) is often associated with disseminated intravascular coagulation (DIC), thus leading to the development of multiple organ dysfunction syndrome (MODS). The aim of this study was to examine the pathophysiological relationships between coagulation, fibrinolysis and fibrinolytic shutdown by evaluating the levels of coagulofibrinolytic markers, including soluble fibrin, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator-plasminogen activator inhibitor-1 complex (tPAIC), plasmin-alpha2 plasmin inhibitor complex (PPIC), neutrophil elastase and fibrin degradation product by neutrophil elastase (EXDP). Materials and Methods: Fifty-two resuscitated patients were divided into two groups: 22 DIC and 30 non-DIC patients. Results: The levels of soluble fibrin, PPIC, tPAIC, EXDP and neutrophil elastase in the DIC patients with PCAS were significantly higher than those observed in the non-DIC patients. The values of the tPAIC and JAAM DIC scores were found to be independent predictors of increased SOFA scores in the DIC patients. The MODS patients demonstrated significantly higher levels of soluble fibrin and tPAIC; however, the levels of TAFI and EXDP were identical between the patients with and without MODS. In addition, positive correlations were observed between the levels of tPAIC and EXDP in the patients with non-MODS; however, no correlations were observed between these markers in the MODS patients. Conclusions: Thrombin activation and fibrinolytic shutdown play important roles in the development of organ dysfunction in PCAS patients. Neutrophil elastase-mediated fibrinolysis cannot overcome the fibrinolytic shutdown that occurs in DIC patients with PCAS, thus resulting in the development of MODS. [Copyright &y& Elsevier]