Serum Proteomics Identified TAFI as a Potential Molecule Facilitating the Migration of Peripheral Monocytes to Damaged White Matter During Chronic Cerebral Hypoperfusion.

Neuroinflammation is assumed as the critical pathophysiologic mechanism of white matter lesions (WMLs), and infiltrated peripheral monocyte-derived macrophages are implicated in the development of neuroinflammation. This study sought to explore the blood molecules that promote the migration of peripheral monocytes to the sites of WMLs. The serum protein expression profiles of patients and Sprague-Dawley rat models with WMLs were detected by data-independent acquisition (DIA) proteomics technique. Compared with corresponding control groups, we acquired 62 and 41 differentially expressed proteins (DEPs) in the serum of patients and model rats with WMLs respectively. Bioinformatics investigations demonstrated that these DEPs were linked to various Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene Ontology (GO) terms involved in neuroinflammation. Afterward, we identified thrombin-activatable fibrinolysis inhibitor (TAFI) as a shared and overexpressed protein in clinical and animal serum samples, which was further verified by enzyme-linked immunosorbent assay. Additionally, an upregulation of TAFI was also observed in the white matter of rat models, and the inhibition of TAFI impeded the migration of peripheral monocytes to the area of WMLs. In vitro experiments suggested that TAFI could enhance the migration ability of RAW264.7 cells and increase the expression of Ccr2. Our study demonstrates that neuroinflammatory signals can be detected in the peripheral blood of WMLs patients and model rats. TAFI may serve as a potential protein that promotes the migration of peripheral monocytes to WMLs regions, thereby providing a novel molecular target for further investigation into the interaction between the central and peripheral immune systems.

Thrombin activatable fibrinolysis inhibitor plasma levels and TAFI Thr325Ile genetic polymorphism in a cohort of Egyptian sickle cell disease patients and impact on disease severity.

BACKGROUND: Thrombin is a critical protease modulating thrombosis as well as inflammation, which are one of the main pathophysiological mechanisms in sickle vasculopathy, and its levels were reported to be high in sickle cell disease (SCD). The thrombin-thrombomodulin complex activates the TAFI inhibitor of fibrinolysis, which acts by reducing plasmin affinity for its substrate thus hindering fibrinolysis. OBJECTIVE: We aimed to determine the influence of the Thr325Ile single nucleotide polymorphism (SNP) on TAFI antigen levels and potential effects on the severity of SCD in a cohort of Egyptian patients. METHODS: Genotyping of Thr325lle polymorphism using Taq-Man SNP genotyping assay and TAFI level measurement using an enzyme-linked immunosorbent assay were performed for 80 SCD patients (45 homozygous HbSS, 16 S/ß0 and 19 Sß+) as well as 80 age- and gender-matched healthy control subjects. RESULTS: Plasma TAFI levels were higher in SCD patients with Thr325Ile polymorphism, yet the difference was not statistically significant (p = .204). SCD patients with polymorphic genotypes had a greater number of hospital admissions (p = .03). Ten patients with acute chest syndrome had the homozygous polymorphic genotype (GG), and all patients with pulmonary hypertension had the polymorphic genotype (six were homozygous [GG] and five were heterozygous [GA]). Patients with SCD complicated with pulmonary hypertension showed significantly higher plasma TAFI levels (p = .044). CONCLUSION: The analysis of Thr325Ile polymorphisms combined with plasma TAFI levels suggests that the analyzed SNP could influence plasma TAFL levels and SCD disease severity and hospitalization rates, which could be predictors for complex disease.

High thrombin-activatable fibrinolysis inhibitor expression in thrombi from stroke patients in elevated estrogen states.

BACKGROUND: The risk of acute ischemic stroke (AIS) associated with high estrogen states, including pregnant patients and those using oral contraceptives, has been well documented. We described the histological composition of thrombi collected in these cases. METHODS: From a prospective tissue registry (STRIP registry) of thrombi retrieved during mechanical thrombectomy for AIS, we identified 5 patients with high estrogen states: 1 post-partum patient, 1 undergoing hormone replacement therapy and 3 consuming oral contraceptive pills. Five male control patients were randomly chosen matched by age. Immunohistochemistry for CD42b (platelets), von Willebrand factor (vWF), thrombin-activatable fibrinolysis inhibitor (TAFI), fibrinogen and plasminogen activator inhibitor-1 (PAI-1) was performed. Expression was quantified using Orbit Image Software. Student's t-test was performed as appropriate. RESULTS: Mean TAFI content for the high estrogen state group was higher than controls (25.6 ± 11.9% versus 9.3 ± 9.0%, p = 0.043*). Mean platelet content for the high estrogen state group was lower than controls (41.7 ± 10.6% versus 61.8 ± 12.9%, p = 0.029*). No significant difference was found in vWF, fibrinogen and PAI-1 expression. Mean time to recanalize was higher in the high estrogen state group compared to the control group (57.8 ± 27.6 versus 22.6 ± 11.4 min, p = 0.0351*). The mean number of passes required was higher in the high estrogen group compared to controls 4.6 versus 1.2, p = 0.0261*). CONCLUSIONS: TAFI expression, a powerful driver of thrombosis, was significantly higher in stroke thrombi among patients with high estrogen states compared to controls.

Serum thrombin-activatable fibrinolysis inhibitor levels and its relation with pathogenesis and bleeding and prognosis in patients with Crimean Congo hemorrhagic fever.

Crimean-Congo hemorrhagic fever (CCHF) is a viral hemorrhagic fever, which is common in Turkey and globally. The pathogenesis of coagulation disorders, which is seen in viral hemorrhagic fevers remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) has a key role in this process In this study, we aimed to evaluate whether TAFI levels contributed to bleeding and whether it is related to prognosis in CCHF patients. Eighty-four patients older than 15 years of age, who were admitted to our hospital who had positive immunoglobulin M (enzyme-linked immunosorbent assay [ELISA]) and/or polymerase chain reaction test results for CCHF between 2009 and 2010, were included in the study. The control group included 30 healthy adults. The plasma TAFI levels were compared between patients and controls, and also between patients with bleeding and no bleeding, and between patients with mild-moderate and severe disease. The mean TAFI levels were lower in patients (mean: 87.82 ng/ml, median: 61.69 ng/ml (interquartile range [IQR] 30.49-537.95) than controls (mean: 313.5 ng/ml with a median: 338.5 ng/ml (IQR 182-418). However, median TAFI levels were significantly higher in patients with bleeding compared to those without bleeding (78.99 and 50.28 ng/ml, respectively; p = 0.032). Median IQR TAFI levels were similar between patients with mild-moderate and severe disease (64.72 (41.37-113.85), and, 58.66 (42.44-118.93) ng/ml, respectively; p = 0.09) and survivors and nonsurvivors (86.14 ± 77.98 and 103.48 ± 69.92, respectively; p = 0.3). Although TAFI levels were lower in the patients with CCHF compared to healthy controls, it does not seem to be a major player in the prognosis.

Profibrinolytic effects of rivaroxaban are mediated by thrombin-activatable fibrinolysis inhibitor and are attenuated by a naturally occurring stabilizing mutation in enzyme.

Rivaroxaban is a direct factor Xa inhibitor, recently implemented as a favorable alternative to warfarin in anticoagulation therapy. Rivaroxaban effectively reduces thrombin generation, which plays a major role in the activation of thrombin activatable fibrinolysis inhibitor (TAFI) to TAFIa. Based on the antifibrinolytic role of TAFIa, we hypothesized that rivaroxaban would consequently induce more rapid clot lysis. In vitro clot lysis assays were used to explore this hypothesis and additionally determine the effects of varying TAFI levels and a stabilizing Thr325Ile polymorphism (rs1926447) in the TAFI protein on the effects of rivaroxaban. Rivaroxaban was shown to decrease thrombin generation, resulting in less TAFI activation, thus enhancing lysis. These effects were also shown to be less substantial in the presence of greater TAFI levels or the more stable Ile325 enzyme. These findings suggest a role for TAFI levels and the Thr325Ile polymorphism in the pharmacodynamics and pharmacogenomics of rivaroxaban.

ProCPU Is Expressed by (Primary) Human Monocytes and Macrophages and Expression Differs between States of Differentiation and Activation.

Carboxypeptidase U (CPU, TAFIa, CPB2) is a potent attenuator of fibrinolysis that is mainly synthesized by the liver as its inactive precursor proCPU. Aside from its antifibrinolytic properties, evidence exists that CPU can modulate inflammation, thereby regulating communication between coagulation and inflammation. Monocytes and macrophages play a central role in inflammation and interact with coagulation mechanisms resulting in thrombus formation. The involvement of CPU and monocytes/macrophages in inflammation and thrombus formation, and a recent hypothesis that proCPU is expressed in monocytes/macrophages, prompted us to investigate human monocytes and macrophages as a potential source of proCPU. CPB2 mRNA expression and the presence of proCPU/CPU protein were studied in THP-1, PMA-stimulated THP-1 cells and primary human monocytes, M-CSF-, IFN-γ/LPS-, and IL-4-stimulated-macrophages by RT-qPCR, Western blotting, enzyme activity measurements, and immunocytochemistry. CPB2 mRNA and proCPU protein were detected in THP-1 and PMA-stimulated THP-1 cells as well as in primary monocytes and macrophages. Moreover, CPU was detected in the cell medium of all investigated cell types and it was demonstrated that proCPU can be activated into functionally active CPU in the in vitro cell culture environment. Comparison of CPB2 mRNA expression and proCPU concentrations in the cell medium between the different cell types provided evidence that CPB2 mRNA expression and proCPU secretion in monocytes and macrophages is related to the degree to which these cells are differentiated. Our results indicate that primary monocytes and macrophages express proCPU. This sheds new light on monocytes and macrophages as local proCPU sources.

[Relationship between plasma levels of thrombin activatable fibrinolysis inhibitor, plasminogen activator inhibitor-1 and tissue-type plasminogen activator and deep venous thrombosis in patients with systemic lupus erythematosus].

Objective: To investigate the plasma levels of thrombin activatable fibrinolysis inhibitor (TAFI), plasminogen activator inhibitor-1 (PAI-1) and tissue-type plasminogen activator (t-PA) in patients with systemic lupus erythematosus (SLE), and their relationship with deep venous thrombosis of the lower limbs. Methods: A case-control study was conducted to retrospectively select 32 SLE patients with deep venous thrombosis of the lower extremities (thrombus group) admitted to Liaocheng People's Hospital in Shandong Province from June 2018 to June 2021, including 4 males and 28 females, with a mean age of (49.7±5.5) years. Meanwhile, 64 SLE patients without deep venous thrombosis of the lower extremities (control group) were also selected, including 11 males and 53 females, with a mean age of (50.8±5.5) years. The plasma levels of TAFI, PAI-1 and t-PA of the two groups were compared. A logistic regression model was used to analyze the correlation of TAFI, PAI-1 and t-PA with SLE in patients. Results: The plasma levels of TAFI, PAI-1 and t-PA were (32.77±5.17) mg/L, (29.43±5.51) µg/L and (6.58±1.40) µg/L in the thrombotic group, while the plasma levels of TAFI, PAI-1 and t-PA in the control group were (23.56±4.40) mg/L, (19.00±4.40) µg/L and (9.40±2.23) µg/L. The levels of TAFI and PAI-1 in the thrombotic group were higher than those in the control group, while the level of t-PA was lower than that in the control group (all P<0.05). The results of logistic regression model showed that higher TAFI levels (OR=1.75, 95%CI: 1.05-2.90, P=0.043), higher PAI-1 levels (OR=1.85, 95%CI: 1.04-3.29, P=0.046), and lower t-PA levels (OR=0.72, 95%CI: 0.52-0.99, P=0.048) were related factors for the occurrence of deep venous thrombosis of the lower limbs in SLE patients. Conclusion: The plasma levels of TAFI and PAI-1 in SLE patients with deep venous thrombosis of the lower extremities increase, while the t-PA level decreases, which are related factors for the occurrence of deep venous thrombosis of the lower extremities in SLE patients.

Assessment of plasminogen activator inhibitor-1(PAI1) and thrombin activitable fibrinolysis inhibitor (TAFI) in Egyptian children with hemophilia A.

Patients with hemophilia A display varied bleeding phenotypes not correlated with degree of deficiency of factor VIII level. We investigated Plasminogen Activator Inhibitor 1(PAI1) level and Thrombin Activatable Fibrinolysis Inhibitor (TAFI) also known as Carboxypeptidase B2 (CPB2) level in Patients with hemophilia A and their possible correlation with bleeding tendency. Twenty-six patients attending in hematology unit of pediatric department were included in this study. In addition, fourteen apparently healthy subjects matched ages and genders were included as control group. The International Society of Thrombosis Bleeding Assessment Tool (ISTH/BAT) was used to assess bleeding score in patients. Plasma levels of Plasminogen Activator Fibrinolysis Inhibitor (PAI1) and Thrombin Activatable Fibrinolysis Inhibitor (TAFI) zymogen were measured by enzyme-linked immunosorbent assay (ELIZA). As compared to controls, hemophilic patients had significantly high bleeding score, low PAI 1 level and high TAFI level. There was no significant correlation between bleeding score by ISTH/BAT and patient severity. PAI 1 and TAFI level have no significant correlation with patient severity. PAI 1 level was statistically significant different between intense and non-intense hemorrhagic groups, while TAFI level has no significant correlation with bleeding phenotype. PAI 1 and TAFI levels had significantly correlation between patients and controls. PAI-1 level had statistically significant correlation with bleeding phenotype, while TAFI level failed to show any correlation between intense and non-intense hemorrhagic groups. So, PAI-1 levels may have predictive value of bleeding tendency in hemophiliacs.

Thrombin Activatable Fibrinolysis Inhibitor (TAFI): An Updated Narrative Review.

Thrombin activatable fibrinolysis inhibitor (TAFI), a proenzyme, is converted to a potent attenuator of the fibrinolytic system upon activation by thrombin, plasmin, or the thrombin/thrombomodulin complex. Since TAFI forms a molecular link between coagulation and fibrinolysis and plays a potential role in venous and arterial thrombotic diseases, much interest has been tied to the development of molecules that antagonize its function. This review aims at providing a general overview on the biochemical properties of TAFI, its (patho)physiologic function, and various strategies to stimulate the fibrinolytic system by interfering with (activated) TAFI functionality.

Carboxypeptidase U (CPU, TAFIa, CPB2) in Thromboembolic Disease: What Do We Know Three Decades after Its Discovery?

Procarboxypeptidase U (proCPU, TAFI, proCPB2) is a basic carboxypeptidase zymogen that is converted by thrombin(-thrombomodulin) or plasmin into the active carboxypeptidase U (CPU, TAFIa, CPB2), a potent attenuator of fibrinolysis. As CPU forms a molecular link between coagulation and fibrinolysis, the development of CPU inhibitors as profibrinolytic agents constitutes an attractive new concept to improve endogenous fibrinolysis or to increase the efficacy of thrombolytic therapy in thromboembolic diseases. Furthermore, extensive research has been conducted on the in vivo role of CPU in (the acute phase of) thromboembolic disease, as well as on the hypothesis that high proCPU levels and the Thr/Ile325 polymorphism may cause a thrombotic predisposition. In this paper, an overview is given of the methods available for measuring proCPU, CPU, and inactivated CPU (CPUi), together with a summary of the clinical data generated so far, ranging from the current knowledge on proCPU concentrations and polymorphisms as potential thromboembolic risk factors to the positioning of different CPU forms (proCPU, CPU, and CPUi) as diagnostic markers for thromboembolic disease, and the potential benefit of pharmacological inhibition of the CPU pathway.

Fibrinogen and Antifibrinolytic Proteins: Interactions and Future Therapeutics.

Thrombus formation remains a major cause of morbidity and mortality worldwide. Current antiplatelet and anticoagulant therapies have been effective at reducing vascular events, but at the expense of increased bleeding risk. Targeting proteins that interact with fibrinogen and which are involved in hypofibrinolysis represents a more specific approach for the development of effective and safe therapeutic agents. The antifibrinolytic proteins alpha-2 antiplasmin (α2AP), thrombin activatable fibrinolysis inhibitor (TAFI), complement C3 and plasminogen activator inhibitor-2 (PAI-2), can be incorporated into the fibrin clot by FXIIIa and affect fibrinolysis by different mechanisms. Therefore, these antifibrinolytic proteins are attractive targets for the development of novel therapeutics, both for the modulation of thrombosis risk, but also for potentially improving clot instability in bleeding disorders. This review summarises the main properties of fibrinogen-bound antifibrinolytic proteins, their effect on clot lysis and association with thrombotic or bleeding conditions. The role of these proteins in therapeutic strategies targeting the fibrinolytic system for thrombotic diseases or bleeding disorders is also discussed.

[Spontaneous fibrinolysis and possibilities of its acceleration in pulmonary embolism]. / Spontannyi fibrinoliz i vozmozhnosti ego uskoreniia pri tromboémbolii legochnoi arterii.

This review contains the data concerning the mechanisms of spontaneous fibrinolysis in pulmonary vessels and possibilities of its acceleration in pulmonary embolism. The spontaneous fibrinolysis system is known to be sequential and multifactorial, with the interaction of accelerators (t-PA and u-PA) and inhibitors (alpha-2-antiplasmin, PAI-1, TAFI). The fibrinolytic processes take place in case of prevailing reactions of accelerating factors over inhibiting ones. The endothelium of pulmonary vessels possesses pronounced antithrombogenic and profibrinolytic properties, therefore, the processes of fibrinolysis in the pulmonary vascular bed normally occur more intensively than in the vessels of the systemic circulation. The membrane proteins of the endothelium annexins A2 activate plasminogen, whereas thrombomodulin inhibits the activity of PAI-1. The main approaches to increase the fibrinolysis intensity in conditions of pulmonary embolism may be aimed at elevating the activity of fibrinolytic enzymes (enhancing the synthesis of annexins A2, the use of NMDA-receptor antagonists) and suppressing its inhibitors (the use of monoclonal antibodies to alpha-2-antiplasmin, as well as plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI). Promising directions for future research can be the synthesis of a new generation of tissue-type plasminogen activators, and investigations of the possibility of clinical application of antithrombin and thrombomodulin, angiotensin converting enzyme inhibitors and cortisol antagonists. To meet these challenges, it is necessary to develop new models of venous thrombosis and acute pulmonary embolism in different animal species, with the assessment of the changes in the venous haemodynamics and pulmonary microcirculation on the background of administration of a new class of fibrinolytic agents.

Rosuvastatin use increases plasma fibrinolytic potential: a randomised clinical trial.

We conducted a study to assess the effect of rosuvastatin use on fibrinolysis in patients with previous venous thromboembolism (VTE). This was a post hoc analysis within the STAtins Reduce Thrombophilia (START) study (NCT01613794). Plasma fibrinolytic potential, fibrinogen, plasmin inhibitor, plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) were measured before and after four weeks of rosuvastatin or no treatment in participants with prior confirmed VTE, after ending anticoagulant therapy. In the non-rosuvastatin group (n = 121), plasma fibrinolytic potential and individual fibrinolysis parameters did not change at the end of the study versus the baseline, whereas in the rosuvastatin group (n = 126), plasma fibrinolytic potential increased: the mean clot lysis time decreased by 8·75 min (95% CI -13·8 to -3·72), and plasmin inhibitor levels and TAFI activity were lower at the end of the study (-0·05 U/ml; 95% CI -0·07 to -0·02 and -4·77%; 95% CI -6·81 to -2·73, respectively). PAI-1 levels did not change and fibrinogen levels were 0·17 g/l (95% CI 0·04-0·29) higher. In participants with prior VTE, rosuvastatin use led to an increased fibrinolytic potential compared with non-statin use. Our findings support the need for further studies on the possible role for statins in the secondary prevention of VTE.

Defective TAFI activation in hemophilia A mice is a major contributor to joint bleeding.

Joint bleeds are common in congenital hemophilia but rare in acquired hemophilia A (aHA) for reasons unknown. To identify key mechanisms responsible for joint-specific bleeding in congenital hemophilia, bleeding phenotypes after joint injury and tail transection were compared in aHA wild-type (WT) mice (receiving an anti-factor VIII [FVIII] antibody) and congenital HA (FVIII-/-) mice. Both aHA and FVIII-/- mice bled severely after tail transection, but consistent with clinical findings, joint bleeding was notably milder in aHA compared with FVIII-/- mice. Focus was directed to thrombin-activatable fibrinolysis inhibitor (TAFI) to determine its potentially protective effect on joint bleeding in aHA. Joint bleeding in TAFI-/- mice with anti-FVIII antibody was increased, compared with WT aHA mice, and became indistinguishable from joint bleeding in FVIII-/- mice. Measurements of circulating TAFI zymogen consumption after joint injury indicated severely defective TAFI activation in FVIII-/- mice in vivo, consistent with previous in vitro analyses in FVIII-deficient plasma. In contrast, notable TAFI activation was observed in aHA mice, suggesting that TAFI protected aHA joints against bleeding. Pharmacological inhibitors of fibrinolysis revealed that urokinase-type plasminogen activator (uPA)-induced fibrinolysis drove joint bleeding, whereas tissue-type plasminogen activator-mediated fibrinolysis contributed to tail bleeding. These data identify TAFI as an important modifier of hemophilic joint bleeding in aHA by inhibiting uPA-mediated fibrinolysis. Moreover, our data suggest that bleed protection by TAFI was absent in congenital FVIII-/- mice because of severely defective TAFI activation, underscoring the importance of clot protection in addition to clot formation when considering prohemostatic strategies for hemophilic joint bleeding.

FVIII/VWF complex displays a greater pro-haemostatic activity than FVIII preparations devoid of VWF: Study in plasma and cell-based models.

INTRODUCTION: Plasma-derived FVIII/VWF complex was reported to be less sensitive to inhibitors than FVIII preparations devoid of VWF. AIM: To compare the efficacy of FVIII/VWF complex (Fanhdi) and five different VWF-free FVIII preparations in restoring thrombin generation and activation of thrombin-activatable fibrinolysis inhibitor (TAFI) in haemophilic plasma, with and without inhibitor, and in cell-based models. METHODS: Experiments were performed in haemophilic plasma supplemented with inhibitory IgG or in plasma samples obtained from haemophilia A patients without (n = 11) and with inhibitor (n = 12). Thrombin generation was evaluated by calibrated automated thrombography (CAT) under standard conditions, in the presence of activated protein C (APC) or thrombomodulin (TM), and in cell-based models including endothelial cells, either alone or in combination with platelets or tissue factor-expressing blood mononuclear cells. The kinetics of TAFI activation was determined by a two-stage functional assay in the absence and in the presence of APC. RESULTS: In haemophilic plasma without inhibitor, Fanhdi enhanced thrombin generation and TAFI activation as well as recombinant (2nd-4th generation) and plasma-derived FVIII preparations devoid of VWF. On the contrary, in plasma with inhibitor, Fanhdi displayed a greater ability to restore thrombin generation and TAFI activation under all tested conditions. Notably, in cell-based models including endothelial cells, Fanhdi proved more efficient than all other preparations in improving thrombin generation even in the absence of inhibitor. CONCLUSION: The greater pro-haemostatic activity of FVIII/VWF complex, either in haemophilic plasma with inhibitor or in the presence of endothelial cells, may offer therapeutic advantages.

Increased thrombin-activatable fibrinolysis inhibitor levels in patients with chronic rhinosinusitis with nasal polyps.

BACKGROUND: Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease subdivided based on the presence or absence of nasal polyps (NPs). Histologic features of chronic rhinosinusitis with nasal polyps (CRSwNP) include inflammatory cell infiltration and excessive fibrin deposition in NPs. Thrombin-activatable fibrinolysis inhibitor (TAFI) is an enzyme that plays an antifibrinolytic role in the body. The significance of TAFI has been documented in patients with chronic inflammatory diseases, including chronic lung disease; however, it has not been evaluated in the pathogenesis of NPs. OBJECTIVE: The objective of this study was to evaluate the potential role of TAFI in the pathogenesis of NPs. METHODS: Nasal lavage fluid was collected from control subjects and patients with CRS. We measured levels of thrombin/anti-thrombin complex (TATc) and TAFI protein using an ELISA. RESULTS: TATc levels in nasal lavage fluid were significantly increased in patients with CRSwNP and patients with chronic rhinosinusitis without nasal polyps (CRSsNP) compared with control subjects, and TAFI levels in nasal lavage fluid were also significantly increased in patients with CRSwNP compared with those in control subjects and patients with CRSsNP. There was a significant correlation between TATc and TAFI levels in nasal lavage fluid. Interestingly, patients with CRS and asthma showed increased TATc and TAFI levels in nasal lavage fluid compared with those in patients with CRS without asthma, especially patients with CRSwNP. CONCLUSIONS: Increased TATc and TAFI levels in nasal passages of patients with CRSwNP might participate in fibrin deposition in NPs and might play a role in the pathogenesis of CRSwNP and asthma.

Activated TAFI Promotes the Development of Chronic Thromboembolic Pulmonary Hypertension: A Possible Novel Therapeutic Target.

RATIONALE: Pulmonary hypertension is a fatal disease; however, its pathogenesis still remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and inhibits fibrinolysis. Plasma TAFI levels are significantly increased in chronic thromboembolic pulmonary hypertension (CTEPH) patients. OBJECTIVE: To determine the role of activated TAFI (TAFIa) in the development of CTEPH. METHODS AND RESULTS: Immunostaining showed that TAFI and its binding partner thrombomodulin (TM) were highly expressed in the pulmonary arteries (PAs) and thrombus in patients with CTEPH. Moreover, plasma levels of TAFIa were increased 10-fold in CTEPH patients compared with controls. In mice, chronic hypoxia caused a 25-fold increase in plasma levels of TAFIa with increased plasma levels of thrombin and TM, which led to thrombus formation in PA, vascular remodeling, and pulmonary hypertension. Consistently, plasma clot lysis time was positively correlated with plasma TAFIa levels in mice. Additionally, overexpression of TAFIa caused organized thrombus with multiple obstruction of PA flow and reduced survival rate under hypoxia in mice. Bone marrow transplantation showed that circulating plasma TAFI from the liver, not in the bone marrow, was activated locally in PA endothelial cells through interactions with thrombin and TM. Mechanistic experiments demonstrated that TAFIa increased PA endothelial permeability, smooth muscle cell proliferation, and monocyte/macrophage activation. Importantly, TAFIa inhibitor and peroxisome proliferator-activated receptor-α agonists significantly reduced TAFIa and ameliorated animal models of pulmonary hypertension in mice and rats. CONCLUSIONS: These results indicate that TAFIa could be a novel biomarker and realistic therapeutic target of CTEPH.

A direct oral anticoagulant edoxaban accelerated fibrinolysis via enhancement of plasmin generation in human plasma: dependent on thrombin-activatable fibrinolysis inhibitor.

A direct oral anticoagulant, edoxaban, is as effective as vitamin K antagonists for the treatment of venous thromboembolism (VTE). However, the mechanism underlying the treatment effect on VTE remains to be determined. The aims of this study were to evaluate the effect of edoxaban on tissue plasminogen activator (t-PA)-induced clot lysis in human plasma and to determine the roles of plasmin and thrombin-activatable fibrinolysis inhibitor (TAFI) in the profibrinolytic effect by edoxaban. Pooled human normal plasma or TAFI-deficient plasma (containing 180 ng/mL t-PA and 0.1 nM thrombomodulin) was mixed with edoxaban or an activated TAFI inhibitor, potato tuber carboxypeptidase inhibitor (PCI). Clot was induced by adding tissue factor and phospholipids. Clot lysis time and plasma plasmin-α2 antiplasmin complex (PAP) concentration were determined. Clot structure was imaged with a scanning electron microscope. In normal plasma, edoxaban at clinically relevant concentrations (75, 150, and 300 ng/mL) and PCI significantly shortened clot lysis time. PCI increased PAP concentration and a correlation between PAP concentration and percent of clot lysis was observed. Edoxaban also dose-dependently elevated PAP concentration. In TAFI-deficient plasma, the effects of edoxaban and PCI on clot lysis and PAP concentration were markedly diminished as compared with normal plasma. Fibrin fibers were thinner in clots formed in the presence of edoxaban. In conclusion, edoxaban at clinically relevant concentrations accelerates t-PA-induced fibrinolysis via increasing plasmin generation in human plasma. The effects of edoxaban is mainly dependent on TAFI. The profibrinolytic effect of edoxaban might contribute to the efficacy for the treatment of VTE.

The prevalence of combined vascular endothelial growth factor, endothelial nitric oxide synthase and thrombin-activatable fibrinolysis inhibitor genetic polymorphisms among Egyptian patients with recurrent spontaneous abortion.

AIM: As angiogenesis is an essential step for chorionic villi formation. Vascular endothelial growth factor (VEGF) is essential for endothelial cell proliferation. Endothelial nitric oxide synthase (eNOS) is a powerful playmaker in hypoxia-induced angiogenesis. Thrombin-activatable fibrinolysis inhibitor (TAFI) regulates both fibrinolysis and inflammation. Genetic alterations of these factors may lead to recurrent spontaneous abortion (RSA). We aimed to investigate the combined genetic variants of VEGF G-1154A and two eNOS genetic variants: T-786C promoter region and intron 4 variable number of tandom repeats in addition to TAFI C-1040T among RSA patients. METHODS: The study included 50 patients with RSA and 50 healthy controls. Polymerase chain reaction and restriction fragment length polymorphism were used for genotyping. RESULTS: Both genetic alterations of eNOS confirmed at least a sixfold increase of RSA risk. Interestingly, they were associated with TAFI C-1040Tgenetic variant in 21 patients, eight of them had both studied eNOS genetic alterations and TAFI C-1040Tgenetic variant, while each eNOS genetic variant associated with TAFI C-1040Tconfirmed an almost one and half fold increase risk of RSA. CONCLUSION: These findings highlighted the role of eNOS and nitric oxide metabolism in RSA and opened the gate to investigate the interaction of vasoconstrictive and fibrinolytic inhibitor systems.

Plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels in acromegaly patients in remission

Background/aim: Acromegaly is associated with increased morbidity andmortality, mostly due to cardiovascular complications.Plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels are associated with coagulation/fibrinolysis and inflammation. Plasma TAFI may play a role in arterial thrombosis in cardiovascular diseases. In this study, it was aimed to evaluate the thrombin-activatable fibrinolysis inhibitor (TAFI) antigen and homocysteine levels in patients with acromegaly and healthy control subjects. Materials and methods: Plasma TAFI antigen and homocysteine levels in 29 consecutive patients with acromegaly and 26 age-matched healthy control subjects were measured. All patients included in the study were in remission. The TAFIa/ai antigen in the plasma samples was measured using a commercially available ELISA kit. Results: Routine biochemical parameters, fasting blood glucose, prolactin, thyroid stimulating hormone, total-cholesterol, low density lipoprotein cholesterol, triglyceride, and homocysteine levels were similar in the 2 groups (P > 0.05), whereas the plasma TAFI antigen levels were significantly elevated in the acromegalic patients (154.7 ± 94.0%) when compared with the control subjects (107.2 ± 61.6%) (P = 0.033). No significant correlation was identified by Pearson's correlation test between the plasma TAFI antigen and homocysteine levels (r = 0.320, P = 0.250). Conclusion: A significant alteration in the plasma TAFI antigen levels was detected in acromegaly. Increased plasma TAFI antigen levels might aggravate prothrombotic and thrombotic events in patients with acromegaly.