Factor XIII and Fibrin Clot Properties in Acute Venous Thromboembolism

Impaired endogenous fibrinolysis status: a potential prognostic predictor in ischemic stroke

Stroke confers a severe global healthcare burden, hence exploring risk factors for stroke occurrence and prognosis is important for stroke prevention and post-stroke management strategies. Endogenous fibrinolysis is a spontaneous physiological protective mechanism that dissolves thrombus to maintain vascular patency. Recently, impaired endogenous fibrinolysis has been considered as a potential novel cardiovascular risk factor, but its link with ischaemic stroke in the past has been underappreciated. In this review, we summarize the latest mechanisms of endogenous fibrinolysis, review the current evidence and data on endogenous fibrinolysis in ischemic stroke. It includes the structure of thrombus in ischemic stroke patients, the effect of fibrin structure on the endogenous fibrinolytic efficiency, and the association between intravenous thrombolytic therapy and endogenous fibrinolysis in ischemic stroke. It also includes the single factors (tissue plasminogen activator, urokinase plasminogen activator, plasminogen activator inhibitor-1, thrombin activatable fibrinolysis inhibitor, complement component 3, complement component 5, alpha-2-antiplasmin, plasmin-alpha-2-antiplasmin complex, and lipoprotein[a]), and the global assessments of endogenous fibrinolysis status (thromboelastography, rotational thromboelastometry, and global thrombosis test), and their potential as predictors to identify occurrence or unfavorable functional outcomes of ischemic stroke. All of these assessments present advantages and limitations, and we suggest that the global thrombosis test may be more appropriate for detecting impaired endogenous fibrinolysis status in ischemic stroke patients.

Oxidative Stress, Persistent Inflammation and Blood Coagulation Alterations in Serum Proteome of Patients with Neovascular Age-Related Macular Degeneration

Neovascular age-related macular degeneration (AMD) is a major cause of irreversible blindness in elderly populations in developed countries. AMD's etiopathology is multifactorial, with strong environmental and genetic components, but the exact molecular pathomechanisms underlying the disease are still unknown. In this study, we analyzed blood serum collected from 74 neovascular AMD patients and 58 healthy controls to identify proteins that may serve as potential biomarkers and expand our knowledge about the etiopathogenesis of the disease. The study revealed 17 differentially expressed proteins-11 up-regulated and 6 down-regulated-in neovascular AMD, which are involved in the biological processes previously linked with the disease-oxidative stress and persistent inflammation, impaired cellular transport, lipid metabolism and blood coagulation. In conclusion, the differences in the expressions of the proteins identified in this study may contribute to our understanding of the mechanisms underlying AMD and possibly serve in future as promising biomarkers.

Thrombotic Disease in Hemophilic Patients: Is This a Paradox in a State of Hypocoagulability?

Hemophilia patients have a deficiency in or dysfunction of clotting factors, which can lead to a bleeding tendency. However, paradoxically, some hemophilia patients may also be at an increased risk of developing thrombotic events such as deep vein thrombosis or pulmonary embolism. The pathophysiology of thrombosis in hemophilia patients is not fully understood, but it is thought to involve a complex interplay of various factors, including the severity of the hemophilia, the presence of other risk factors such as obesity, smoking, or the use of hormonal therapies, and the presence of certain genetic mutations that increase the risk of thrombosis. In addition, it has been suggested that the use of clotting factor replacement therapy, which is a standard treatment for hemophilia, may also contribute to the development of thrombosis in some cases.

Characterization of a recombinant factor IX molecule fused to coagulation factor XIII-B subunit

INTRODUCTION AND AIM

Severe haemophilia B (HB) is characterized by spontaneous bleeding episodes, mostly into joints. Recurrent bleeds lead to progressive joint destruction called haemophilic arthropathy. The current concept of prophylaxis aims at maintaining the FIX level >3-5 IU/dL, which is effective at reducing the incidence of haemophilic arthropathy. Extended half-life FIX molecules make it easier to achieve these target trough levels compared to standard FIX concentrates. We previously reported that the fusion of a recombinant FIX (rFIX) to factor XIII-B (FXIIIB) subunit prolonged the half-life of the rFIX-LXa-FXIIIB fusion molecule in mice and rats 3.9- and 2.2-fold, respectively, compared with rFIX-WT. However, the mechanism behind the extended half-life was not known.

MATERIALS AND METHODS

Mass spectrometry and ITC were used to study interactions of rFIX-LXa-FXIIIB with albumin. Pharmacokinetic analyses in fibrinogen-KO and FcRn-KO mice were performed to evaluate the effect of albumin and fibrinogen on in-vivo half-life of rFIX-LXa-FXIIIB. Finally saphenous vein bleeding model was used to assess in-vivo haemostatic activity of rFIX-LXa-FXIIIB.

RESULTS AND CONCLUSION

We report here the key interactions that rFIX-LXa-FXIIIB may have in plasma are with fibrinogen and albumin which may mediate its prolonged half-life. In addition, using the saphenous vein bleeding model, we demonstrate that rFIX-FXIIIB elicits functional clot formation that is indistinguishable from that of rFIX-WT.

The Fibrinolytic System and Its Measurement: History, Current Uses and Future Directions for Diagnosis and Treatment

The fibrinolytic system is a key player in keeping the haemostatic balance, and changes in fibrinolytic capacity can lead to both bleeding-related and thrombosis-related disorders. Our knowledge of the fibrinolytic system has expanded immensely during the last 75 years. From the first successful use of thrombolysis in myocardial infarction in the 1960s, thrombolytic therapy is now widely implemented and has reformed treatment in vascular medicine, especially ischemic stroke, while antifibrinolytic agents are used routinely in the prevention and treatment of major bleeding worldwide. Despite this, this research field still holds unanswered questions. Accurate and timely laboratory diagnosis of disturbed fibrinolysis in the clinical setting remains a challenge. Furthermore, despite growing evidence that hypofibrinolysis plays a central role in, e.g., sepsis-related coagulopathy, coronary artery disease, and venous thromboembolism, there is currently no approved treatment of hypofibrinolysis in these settings. The present review provides an overview of the fibrinolytic system and history of its discovery; measurement methods; clinical relevance of the fibrinolytic system in diagnosis and treatment; and points to future directions for research.

Potential anticoagulant of traditional chinese medicine and novel targets for anticoagulant drugs

BACKGROUND

Anticoagulants are the main drugs used for the prevention and treatment of thrombosis. Currently, anticoagulant drugs are primarily multitarget heparin drugs, single-target FXa inhibitors and FIIa inhibitors. In addition, some traditional Chinese drugs also have anticoagulant effects, but they are not the main direction of treatment at present. But the anticoagulant drugs mentioned above, all have a common side effect is bleeding. Many other anticoagulation targets are under investigation. With further exploration of coagulation mechanism, how to further determine new anticoagulant targets and how to make traditional Chinese medicine play anticoagulant role have become a new field of exploration.

PURPOSE

The purpose of the study was to summarize the recent research progress on coagulation mechanisms, new anticoagulant targets and traditional Chinese medicine.

METHODS

A comprehensive literature search was conducted using four electronic databases, including PubMed, Embase, CNKI, Wanfang database and ClinicalTrials.gov, from the inception of the study to 28 Feb 2023. Key words used in the literature search were "anticoagulation", "anticoagulant targets", "new targets", "coagulation mechanisms", "potential anticoagulant", "herb medicine", "botanical medicine", "Chinese medicine", "traditional Chinese medicine", "blood coagulation factor", keywords are linked with AND/OR. Recent findings on coagulation mechanisms, potential anticoagulant targets and traditional Chinese medicine were studied.

RESULTS

The active components extracted from the Chinese medicinal herbs, Salvia miltiorrhiza, Chuanxiong rhizoma, safflower and Panax notoginseng have obvious anticoagulant effects and can be used as potential anticoagulant drugs, but the risk of bleeding is unclear. TF/FVIIa, FVIII, FIX, FXI, FXII, and FXIII have all been evaluated as targets in animal studies or clinical trials. FIX and FXI are the most studied anticoagulant targets, but FXI inhibitors have shown stronger advantages.

CONCLUSION

This review of potential anticoagulants provides a comprehensive resource. Literature analysis suggests that FXI inhibitors can be used as potential anticoagulant candidates. In addition, we should not ignore the anticoagulant effect of traditional Chinese medicine, and look forward to more research and the emergence of new drugs.

Thrombomodulin activation driven by LXR agonist attenuates renal injury in diabetic nephropathy

Objective

Inflammation and thrombosis are recognized as interrelated biological processes. Both thrombomodulin (TM) and factor XIII-A (FXIII-A) are involved in inflammation and coagulation process. However, their role in the pathogenesis of diabetic nephropathy (DN) remains unclear. In vitro study, the liver X receptor (LXR) agonist T0901317 can up-regulate the expression of TM in glomerular endothelial cells. Now we evaluated the interaction between TM activation and FXIII-A and their effects against renal injury.

Methods

We first evaluated the serum levels of FXIII-A and TM and the expression of TM, LXR-α and FXIII-A in renal tissues of patients with biopsy-proven DN. We then analyzed the expression of TM, LXR-α and FXIII-A in renal tissues of db/db DN mice after upregulating TM expression via T0901317 or downregulating its expression via transfection of TM shRNA-loaded adenovirus. We also investigated the serum levels of Tumor necrosis factor (TNF)-α, Interleukin (IL)-6, creatinine, and urinary microalbumin level in db/db mice.

Results

Our study showed that elevations in serum levels of FXIII-A positively correlated to the serum levels of TM and were also associated with end-stage kidney disease in patients with DN. The number of TM⁺ cells in the renal tissues of patients with DN negatively correlated with the number of FXIII-A⁺ cells and positively correlated with the number of LXR-α⁺ cells and estimated glomerular filtration rate (eGFR), whereas the number of FXIII-A⁺ cells negatively correlated with the eGFR.

Conclusion

Thrombomodulin activation with T0901317 downregulated FXIII-A expression in the kidney tissue and alleviated renal injury in db/db mice.

Fibrinogen and Factor XIII in Venous Thrombosis and Thrombus Stability

As the third most common vascular disease, venous thromboembolism is associated with significant mortality and morbidity. Pathogenesis underlying venous thrombosis is still not fully understood. Accumulating data suggest fibrin network structure and factor XIII-mediated crosslinking are major determinants of venous thrombus mass, composition, and stability. Understanding the cellular and molecular mechanisms mediating fibrin(ogen) and factor XIII production and function and their ability to influence venous thrombogenesis and resolution may inspire new anticoagulant strategies that target these proteins to reduce or prevent venous thrombosis in certain at-risk patients. This article summarizes fibrinogen and factor XIII biology and current knowledge of their function during venous thromboembolism.

Fibrinogen β chain and FXIII polymorphisms affect fibrin clot properties in acute pulmonary embolism

BACKGROUND

Prothrombotic fibrin clot properties, including increased clot density, are in part genetically determined. We investigated whether fibrinogen alpha-chain gene (FGA) c.991A>G (rs6050), fibrinogen beta chain gene (FGB) -455G>A (rs1800790) and factor XIII gene (F13) c.103G>T (rs5985) polymorphisms affect plasma fibrin clot properties in patients with acute pulmonary embolism (PE).

METHODS

As many as 126 normotensive patients with PE, free of cancer, were genotyped by TaqMan assay. Fibrin clot permeability (K_s ), clot lysis time (CLT) and endogenous thrombin potential (ETP) were assessed on admission.

RESULTS

The minor allele frequencies were as follows: FGA rs6050 (n = 62, 0.31), FGB rs1800790 (n = 40, 0.17) and F13 rs5985 (n = 49, 0.23). There were no differences related to any of the polymorphisms with regard to demographic, clinical and laboratory data, except for fibrinogen concentration, which was higher in carriers of F13 rs5985 polymorphism (p = .024), and PE combined with deep-vein thrombosis, which was less prevalent in FGB rs1800790 polymorphism carriers (p = .004). Carriers of FGB rs1800790 A allele and F13 rs5985 T allele had lower K_s , prolonged CLT and higher ETP compared with major homozygotes (all p < .05). After adjustment for fibrinogen, all differences remained significant (all p < .01). There were no associations between the FGA rs6050 polymorphism and K_s , CLT or ETP.

CONCLUSION

Our study showed that FGB rs1800790 and F13 rs5985 polymorphisms contribute to the prothrombotic fibrin clot phenotype and these effects are strong enough to be observed in the acute phase of PE.

Malignant cerebral infarction after ChAdOx1 nCov-19 vaccination: a catastrophic variant of vaccine-induced immune thrombotic thrombocytopenia

Vaccine-induced thrombotic thrombocytopenia with cerebral venous thrombosis is a syndrome recently described in young adults within two weeks from the first dose of the ChAdOx1 nCoV-19 vaccine. Here we report two cases of malignant middle cerebral artery (MCA) infarct and thrombocytopenia 9-10 days following ChAdOx1 nCoV-19 vaccination. The two cases arrived in our facility around the same time but from different geographical areas, potentially excluding epidemiological links; meanwhile, no abnormality was found in the respective vaccine batches. Patient 1 was a 57-year-old woman who underwent decompressive craniectomy despite two prior, successful mechanical thrombectomies. Patient 2 was a 55-year-old woman who developed a fatal bilateral malignant MCA infarct. Both patients manifested pulmonary and portal vein thrombosis and high level of antibodies to platelet factor 4-polyanion complexes. None of the patients had ever received heparin in the past before stroke onset. Our observations of rare arterial thrombosis may contribute to assessment of possible adverse effects associated with COVID-19 vaccination.

Vaccination is an effective strategy in suppressing COVID-19 pandemic, but rare adverse effects have been reported, including cerebral venous thrombosis. Here the authors report two cases of middle cerebral artery infarct within 9-10 days following ChAdOx1 nCov-19 vaccination that also manifest pulmonary and portal vein thrombosis.