Haemostasis and Thrombosis Research Papers (original) (raw)

2025

Surgical removal of malignant tumors is a mainstay in controlling most solid cancers. However, surgical insult also increases the risk of tumor recurrence and metastasis. Tissue trauma activates the innate immune system locally and systemically, mounting an inflammatory response. Platelets and neutrophils are two crucial players in the early innate immune response that heals tissues, but their actions may also contribute to cancer cell dissemination and distant metastasis. Here we report that surgical stress-activated platelets enhance the formation of platelet-tumor cell aggregates, facilitating their entrapment by neutrophil extracellular traps (NET) and subsequent distant metastasis. A murine hepatic ischemia/reperfusion (I/R) injury model of localized surgical stress showed that I/R promotes capturing of aggregated circulating tumor cells (CTC) by NETs and eventual metastasis to the lungs, which are abrogated when platelets are depleted. Hepatic I/R also increased deposition of NETs within the lung microvasculature, but depletion of platelets had no effect. TLR4 was essential for platelet activation and platelet-tumor cell aggregate formation in an ERK5-GPIIb/ IIIa integrin-dependent manner. Such aggregation facilitated NET-mediated capture of CTCs in vitro under static and dynamic conditions. Blocking platelet activation or knocking out TLR4 protected mice from hepatic I/R-induced metastasis with no CTC entrapment by NETs. These results uncover a novel mechanism where platelets and neutrophils contribute to metastasis in the setting of acute inflammation. Targeted disruption of the interaction between platelets and NETs holds therapeutic promise to prevent postoperative distant metastasis. Significance: Targeting platelet activation via TLR4/ERK5/integrin GPIIb/IIIa signaling shows potential for preventing NET-driven distant metastasis in patients post-resection.

2025, Journal of Biological Chemistry

2025, Journal of Thrombosis and Haemostasis

Studies have shown that high molecular weight kininogen (HK), single chain urokinase (ScuPA), and factor XII (XII) compete each's binding to the urokinase plasminogen activator receptor (uPAR). New studies show outside-in signaling or its regulation through uPAR by these proteins. Methods: Using antibodies to phospho and total ERK1/2 or Akt, immunoblot investgations were performed. Further, the influence of ScuPA or FXII on HUVEC proliferation and growth was ascertained. Results: ScuPA (4-200 nM) or XII (3-200 nM) in the presence of 0.05 mM Zn2+ stimulates ERK1/2 (MAPK 42 and 44) and Akt (Ser473) phosphorylation in endothelial cells (HUVEC). ScuPA or XII phosphorylation of ERK1/2 is blocked by PD98059, but partially decreased by wortmannin or LY294002. Akt phosphorylation (Ser473) by ScuPA or XII is blocked by wortmannin or LY294002, but not by PD98059. The region on uPAR that mediates this signaling is the same 22 amino acid sequence on uPAR domain 2 (D2) (peptides LRG20, PGS20) that binds ScuPA, XII, HK, and vitronectin. Cleaved HK (HKa) or peptide (HKH20) from the HK domain 5(D5) cell binding region block HUVEC ERK1/2 phosphorylation. Activated forms of ScuPA or XII were not required for signaling and cholesterol depletion had no influence. Antibody 6S6 to beta-1-integrin blocks ScuPAor XII-induced phosphorylation of ERK1/2 or Akt. Investigations also show that ScuPA or XII induces HUVEC proliferation and growth and these activities are blocked by the same inhibitors, peptides and antibodies that block ERK1/2 or Akt phosphorylation. Conclusions: These studies indicate that uPAR mediates ScuPA and XII outside-in signaling and activated forms of kininogen regulate these cellular activities connected to apoptosis and angiogenesis.

2025, Journal of Thrombosis and Haemostasis

See also Zamolodchikov D, Renne T, Strickland S. The Alzheimer's disease peptide Ab promotes thrombin generation through activation of coagulation factor XII. This issue, pp 995-1007. Before it was known that a form of AbPP was the cellsecreted proteinase inhibitor PN2, PN2 was recognized as an inhibitor of epidermal growth factor binding protein, trypsin, and chymotrypsin [9]. PN2/AbPP is a tight binding inhibitor of factor XIa (FXIa) with a K i of 2.9 9 10 À10 mol L À1 and, in the presence of Zn 2+ , heparin, or fibrillar Ab, K i ~2.8-6.9 9 10 À11 mol L À1 [10]. The KPI domain of AbPP and AbPP751 also inhibits FIXa (K i = 1.9 9 10 À9 mol L À1 ), FXa (K i = 1.9 9 10 À7 mol L À1 ), and FVIIa-tissue factor (K i = 7.8 9 10 À8 mol L À1 ) . However, it does not inhibit a-thrombin or FXIIa.

2025, Food Research

One of the potential hypoglycaemic food from Indonesia is tempe. The use of germinated soybean and the extended fermentation time are potential methods to increase hypoglycaemic activity. In this study, the potential hypoglycaemic activity of tempe due to the use of germinated soybeans as raw material and the extended fermentation time (observation of 48, 72, and 96 hrs) was evaluated. The observations included insulinotropic free amino acids, soluble protein, peptides profile, antioxidants capacity, isoflavones, total phenolic compounds, and the α-glucosidase inhibitor activity. During the extended fermentation time from 48 hrs to 96 hrs, the germinated soy tempe had the highest insulinotropic free amino acids level, while non-germinated soy tempe had the highest antioxidant components (isoflavones, total phenolic compounds, and antioxidants capacity). However, the activity of α-glucosidase inhibitor due to treatments was decreased, suspiciously related to the decrease of the 11.40 kDa peptide, which was dominant in this study. This study showed that the extended fermentation time from 48 to 96 hrs and the use of germinated soybean was able to increase the tempe hypoglycaemic potencies based on the insulinotropic free amino acids and antioxidant component, but not for α-glucosidase activity.

2025, Journal of Thrombosis and Haemostasis

 Reactive oxygen species (ROS) generation by NOX2 plays a critical role in platelet activation.  Rac1 regulation of NOX2 is important for ROS generation.  Small molecule inhibitor of the Rac1-p67 phox interaction prevents platelet... more

2025, European Heart Journal Supplements

SARS-CoV-2 infection is associated with frequent thrombotic events, at the micro and macro-vascular level, due to the perpetuation of a state of hypercoagulability. The so-called ‘COVID-19 associated coagulopathy’ (CAC) represents a key aspect in the genesis of organ damage from SARS-CoV-2. The main coagulative alterations described in the literature are represented by high levels of D-dimer and fibrinogen. Although CAC has some common features with disseminated intravascular coagulation and sepsis-induced coagulopathy, there are important differences between these clinical pictures and the phenotype of CAC is unique. The pathogenesis of CAC is complex and is affected by the strong interconnection between the inflammatory system and coagulation, in the phenomenon of immunothrombosis and thrombo-inflammation. Several mechanisms come into play, such as inflammatory cytokines, neutrophils, the complement system as well as an alteration of the fibrinolytic system. Finally, an altered pl...

2025, Journal of preventive medicine and hygiene

2025, Journal of Thrombosis and Haemostasis

Background-von Willebrand factor (VWF) variant c.2771G>A; p.R924Q has been described as a benign polymorphism or a possible marker for a null allele and been associated with mild bleeding phenotypes. It was identified in several patients in recent type 1 von Willebrand disease (VWD) studies. Objectives-To determine whether the p.R924Q allele contributes to reduced VWF levels and type 1 VWD. Methods-1115 healthy controls and 148 index cases from the MCMDM-1VWD study were genotyped for c.2771G>A; VWF and FVIII levels were analysed in ABO blood group stratified individuals and the p.R924Q variant was expressed in 293 EBNA cells.

2025, JMV-Journal de Médecine Vasculaire

Background/Aim. -Long-term use of low-molecular-weight heparins (LMWH) for the treatment of cancer-associated thrombosis (CAT) has been well-established. Conversely, the use of thromboprophylaxis in patients with cancer remains controversial in the absence of homogeneous guidelines. Our aim was to assess the awareness of treatment guidelines and the management of patients with CAT in daily clinical practice.

2025, Journal of Thrombosis and Haemostasis

2025, Journal of Vascular Access

Catheter-related right atrial thrombosis is a severe and life-threatening complication of central venous catheters in both adult and young patients. Catheter-related right atrial thrombosis can occur with any type of central venous catheters, utilized either for hemodialysis or infusion. Up to 30% of patients with central venous catheter are estimated to be affected by catheter-related right atrial thrombosis; however, neither precise epidemiological data nor guidelines regarding medical or surgical treatment are available. This complication seems to be closely associated with positioning of the catheter tip in the atrium, whereas it is unlikely with a tip located within superior vena cava. Herein, we report the case of a patient affected by catheter-related right atrial thrombosis, who showed a quick resolution of thrombosis with a new therapeutic scheme combining loco-regional thrombolytic therapy (urokinase as a locking solution) and systemic anticoagulation therapy (vitamin K antagonists), thus avoiding catheter removal. Neither complications of the combination therapy were reported, nor recurrence of catheter-related right atrial thrombosis occurred. In conclusion, the combination therapy here described was safe, quick and effective, achieving the goal of not removing the catheter.

2025, Thrombosis and Haemostasis

Intermediate–high-risk pulmonary embolism (PE) is characterized by right ventricular (RV) dysfunction and elevated circulating cardiac troponin levels despite apparent hemodynamic stability at presentation. In these patients, full-dose systemic thrombolysis reduced the risk of hemodynamic decompensation or death but increased the risk of life-threatening bleeding. Reduced-dose thrombolysis may be capable of improving safety while maintaining reperfusion efficacy. The Pulmonary Embolism International THrOmbolysis (PEITHO)-3 study (ClinicalTrials.gov Identifier: NCT04430569) is a randomized, placebo-controlled, double-blind, multicenter, multinational trial with long-term follow-up. We will compare the efficacy and safety of a reduced-dose alteplase regimen with standard heparin anticoagulation. Patients with intermediate–high-risk PE will also fulfill at least one clinical criterion of severity: systolic blood pressure ≤110 mm Hg, respiratory rate >20 breaths/min, or history of he...

2025

Cardiovascular disease (CVD) is the leading cause of mortality among diabetic patients. Glycation is a nonenzymatic, post translational process where sugars bind to proteins, and it is accelerated in diabetes. Glycation may alter protein structure and function. Von Willebrand Factor (VWF) is a key player in coagulation, and its glycation could potentially exacerbate the pro-thrombotic state associated with diabetes. We hypothesize that glycation of VWF contributes to the progression of macrovascular complications by altering its interactions with key hemostatic partners, such as Factor VIII, platelets (via GPIbα binding), and ADAMTS-13 thereby promoting hypercoagulability and endothelial dysfunction. This hypothesis highlights a functional link between chronic hyperglycemia and macrovascular complications in diabetes. To test this hypothesis, mapping glycation of sites of VWF using mass spectrometry and validating its role as a biomarker using patient-derived samples and highthroughput assays is proposed. If confirmed, this mechanism could provide a novel biomarker for the early detection of high-risk patients and open up new therapeutic targets to manage cardiovascular complications aimed at mitigating cardiovascular disease and improving patient outcomes.

2025, Thrombosis and Haemostasis

Background One year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic by the World Health Organization (WHO) and despite the implementation of mandatory physical barriers and social distancing, humanity remains challenged by a long-lasting and devastating public health crisis. Management Non-pharmacological interventions (NPIs) are efficient mitigation strategies. The success of these NPIs is dependent on the approval and commitment of the population. The launch of a mass vaccination program in many countries in late December 2020 with mRNA vaccines, adenovirus-based vaccines, and inactivated virus vaccines has generated hope for the end of the pandemic. Current Issues The continuous appearance of new pathogenic viral strains and the ability of vaccines to prevent infection and transmission raise important concerns as we try to achieve community immunity against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and its variants. The need of a ...

2025, Journal of Thrombosis and Haemostasis

Background: The ISTH Bleeding Assessment Tool (ISTH-BAT) has been validated for clinical screening of suspected von Willebrand disease (VWD) and for bleeding prediction. Recently it has been validated for subjects with inherited platelet disorders (IPD) (BAT-VAL study). Objectives: To determine whether the ISTH-BAT bleeding score (BS) predicts subsequent bleeding events requiring treatment in IPD patients.

2025, Journal of Thrombosis and Haemostasis

Bleeding symptoms are frequently reported even in otherwise healthy subjects, and differentiating a normal subject from a patient with a mild bleeding disorder (MBD) can be extremely challenging. The concept of bleeding rate, that is, the number of bleeding episodes occurring within a definite time, could be used as the unifying framework reconciling the bleeding risk observed in congenital and acquired coagulopathies into a single picture. For instance, primary prevention trials have shown that the incidence of non-major bleeding symptoms in normal subjects is around five per 100 person-years, and this figure is in accordance with the number of hemorrhagic symptoms reported by normal controls in observational studies on hemorrhagic disorders. The incidence of non-major bleeding in patients with MBDs (e.g. in patients with type 1 VWD carrying the C1130F mutation) is also strikingly similar with that of patients taking antiplatelet drugs, and the incidence in moderately severe bleeding disorders (e.g. type 2 VWD) parallels that of patients taking vitamin K antagonists. The severity of a bleeding disorder may therefore be explained by a bleeding rate model, which also explains several common clinical observations. Appreciation of the bleeding rate of congenital and acquired conditions and of its environmental/genetic modifiers into a single framework will possibly allow the development of better prediction tools in the coming years and represents a major scientific effort to be pursued.

2025, Journal of Thrombosis and Haemostasis

Von Willebrand disease (VWD) is characterized by a wide heterogeneity of clinical and laboratory phenotypes. The complexity of the phenotype is further increased by a highly variable removal rate of von Willebrand factor (VWF) released by desmopressin, which is independent of postinfusion peak level. After the initial demonstration that a reduced VWF survival is present in patients with R1205H mutation (VWD Vicenza), several other mutations, mostly occurring in the VWF D3 domain, have been shown to be associated with accelerated removal of released VWF. Normal subjects with O blood group show reduced survival after desmopressin, underlining the role of different VWF glycosylation present in ABO blood group. Recent evidence suggests that liver and spleen macrophages are responsible for VWF clearance through uptake and endocellular degradation, but it is still not known why some VWF mutants are more prone to increased clearance.

2025, Journal of Thrombosis and Haemostasis

2025, Clinical Orthopaedics and Related Research

The use of different types of antithrombotic prophylactics in various clinical settings was examined. A standardized questionnaire was mailed to 5000 randomly selected practicing orthopaedic surgeons that detailed practice profile, surgical case type and frequency, method of thromboembolism prophylaxis used, incidence of morbidity, and type of screening used. Twenty-one percent (n = 1046) of surgeons surveyed returned the questionnaire. Four of 5 surgeons performing elective hip arthroplasty used some form of thromboembolic prophylaxis for all of their patients, 13% used prophylaxis only for patients considered to be at high risk, and 3% of respondents never used prophylaxis. The rates of prophylactic use for patients undergoing elective knee arthroplasty were similar. A considerably lower rate of routine prophylactic use was seen among surgeons performing surgery for pelvic and lower extremity trauma. Except for cases involving neurologic compromise, most patients undergoing either elective or traumatic spinal surgery were not given prophylaxis. Low dose warfarin alone was the most

2025, Thrombosis and Haemostasis

Background Residual venous obstruction (RVO) is considered a risk factor of recurrence and possibly other clinical outcomes following deep vein thrombosis (DVT). Current guidelines do not support an RVO-tailored duration of anticoagulant therapy; contemporary data of such management strategies are scarce. We aimed to evaluate an RVO-based management strategy and to assess associations of RVO with recurrence, post-thrombotic syndrome (PTS), arterial events and cancer. To gain further insight, D-dimer levels were measured 1 month after stopping anticoagulant therapy. Methods Consecutive patients with symptomatic, proximal DVT were treated in a 2-year clinical care pathway (CCP) at Maastricht University Medical Center and were followed up to 5 years. RVO was assessed at the end of regular duration of anticoagulant therapy, which was extended once if RVO was detected. The study was approved by the medical ethics committee. Result From a total of 825 patients, 804 patients (97.5%) comple...

2025, The Journal of Cardiovascular Aging

Introduction: The link between low-density lipoprotein/high-density lipoprotein (LDL/HDL ratio, LHR) and the prevalence of hypertension in large populations, especially among individuals aged 20 and older, has not been extensively explored. This research aims to examine whether LHR is associated with hypertension prevalence. Methods: This retrospective cohort analysis drew on cross-sectional data from a health checkup database located in China. Hypertension is classified as a systolic blood pressure (SBP) of ≥ 140 mmHg or a diastolic blood pressure (DBP) of ≥ 90 mmHg. Multivariable logistic regression was used to examine the association between LHR and hypertension prevalence. Furthermore, a subgroup analysis was performed to assess how this association varied across different demographic categories. Results: The cross-sectional evaluation encompassed 113,912 participants. After adjusting for confounding variables, every unit rise in LHR correlated with an 11% increase in the prevalence of hypertension (Odds Ratio [OR] = 1.11, 95% Confidence Interval [CI]: 1.06, 1.16). Our findings indicated a nonlinear relationship between LHR and hypertension prevalence, with an inflection point at 2.28. Below this level, each unit increase in LHR was linked to a 168% heightened risk of hypertension, while above this point, the correlation became insignificant. The subgroup analysis indicated that females, older adults, non-smokers, and individuals with lower body mass index (BMI) exhibited a particularly high prevalence of hypertension associated with higher LHR levels. Conclusion: The findings suggest that a higher LHR serves as a notable predictor of hypertension and elevated blood pressure among Chinese adults aged 20 and older. The identified nonlinear relationship and threshold effect highlight the importance of LHR in hypertension screening and management.

2025, Journal of Thrombosis and Haemostasis

• Tumor cells circulating in blood (CTC) may favor thrombotic events in cancer patients. • We assessed the impact of CTC on the risk of thrombosis in metastatic breast cancer. • Baseline CTC detection was the only independent factor associated with the risk of thrombosis. • CTC detection under therapy may be the hidden link between tumor progression & thrombosis. Summary. Background: Circulating tumor cell (CTC) count is a major prognostic factor in metastatic breast cancer (MBC) and has been reported to be associated with thrombosis in short-term studies on MBC patients. Objective: To assess whether CTC detection (CellSearch Ò ) before first-line chemotherapy impacts the risk of thrombosis throughout the course of MBC. Patients/Methods: Among patients included before first-line chemotherapy for MBC in the prospective IC2006-04 CTC detection study (NCT00898014), the electronic medical files of those patients treated at Institut Curie (Paris, France) were searched in silico and manually checked for incident venous or arterial thrombotic events (TE) in the course of MBC. Univariate and multivariate analyses were performed using Cox and Fine-Gray models, adjusted for age and Khorana score. Results/Conclusions: With a median follow-up of 64 months (25-81 months), among the 142 patients included, 34 (24%) experienced a TE (incidence rate, 8 TE/100 patient-years). The TE incidence rate was 13 TE/100 patient-years for the 80 patients with ≥ 1 CTC/7.5 mL of blood before initiating first-line chemotherapy, vs. only 4 TE/100 patient-years for the 62 CTC-negative patients. Fine-Gray multivariate analysis (with death as competing event) included age, Khorana score and baseline lactate dehydrogenase and CTC levels: detectable CTC was the only factor significantly associated with an increased risk of TE (sub-distribution hazard ratio [SHR] for patients with [1-4] CTC = 3.1, 95% CI [1.1; 8.6], SHR for patients with ≥ 5 CTC = 1.4, 95% CI [0.5; 4.6]). This study shows that CTC detection before starting first-line chemotherapy is an independent risk factor for TE in MBC patients.

2025, Journal of Thrombosis and Haemostasis

Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre -including this research content -immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

2025, Journal of Thrombosis and Haemostasis

• Congenital thrombotic thrombocytopenic purpura (cTTP) is a very rare thrombotic microangiopathy. • Its rarity and great phenotype heterogeneity may account for misdiagnosis. • We report the history of a middle-aged woman with cTTP, misdiagnosed until adulthood. • Accurate clinical history is crucial for early diagnosis to prevent long-term sequelae. Summary. Thrombotic thrombocytopenic purpura (TTP) is an acute life-threatening disorder characterized by multiple organ ischemia due to disseminated thrombus formation in the microvasculature. The congenital form of the disease (Upshaw-Schulman syndrome) is related to ADAMTS13 mutations. Adulthood-onset of TTP does not exclude the congenital form of the disease and a diagnostic delay may account for a great morbidity burden in these patients. We describe the case of a middle-aged woman who presented to our attention with a clinical diagnosis of a chronic relapsing form of TTP. The medical history of the patient raised the suspicion of a congenital form of TTP. Phenotype and genotype tests were performed, and clinical diagnosis was confirmed. Upshaw-Schulman syndrome is a rare congenital disease with a great phenotype heterogeneity that can be diagnosed also in adulthood. Accurate clinical history is crucial. Early diagnosis can prevent recurrences and longterm organ damage with long-term sequelae.

2025, Thrombosis and Haemostasis

SummaryCongenital thrombotic thrombocytopenic purpura (TTP) is a rare form of thrombotic microangiopathy, inherited with autosomal recessive mode as a dysfunction or severe deficiency of ADAMTS-13 (A Disinte-grin And Metalloprotease with ThromboSpondin 1 repeats Nr. 13), caused by mutations in the ADAMTS-13 gene. About 100 mutations of the ADAMTS-13 gene were identified so far, although only a few char-acterised by in vitro expression studies. A new Asp to Gly homozygous mutation at position 173 of ADAMTS-13 sequence was identified in a family of Romanian origin, with some members affected by clinical signs of TTP. In two male sons, this mutation caused a severe (< 3 %) deficiency of ADAMTS-13 activity and antigen level, associated with periodic thrombocytopenia, haemolytic anaemia and mild mental confusion. Both parents, who are cousins, showed the same mutation in heterozygous form. Expression studies of the mutant ADAMTS-13, performed in HEK293 cells, showed a severe decrease ...

2025, Thrombosis and Haemostasis

Background Accumulating evidence suggests that circulating amyloidβ 1–40 (Αβ1–40), a proatherogenic aging peptide, may serve as a novel biomarker in cardiovascular disease (CVD). We aimed to explore the role of plasma Αβ1–40 and its patterns of change over time in atherosclerosis progression in postmenopausal women, a population with substantial unrecognized CVD risk beyond traditional risk factors (TRFs). Methods In this prospective study, Αβ1–40 was measured in plasma by enzyme-linked immunosorbent assay and atherosclerosis was assessed using carotid high-resolution ultrasonography at baseline and after a median follow-up of 28.2 months in 152 postmenopausal women without history or symptoms of CVD. Results At baseline, high Αβ1–40 was independently associated with higher carotid bulb intima-media thickness (cbIMT) and the sum of maximal wall thickness in all carotid sites (sumWT) (p < 0.05). Αβ1–40 levels increased over time and were associated with decreasing renal function (...

2025, Journal of Thrombosis and Haemostasis

Fibrinogen binding to platelets triggers a IIb b 3dependent outside-in signals that promote actin rearrangements and cell spreading. Studies with chemical inhibitors or activators have implicated protein kinase C (PKC) in a IIb b 3 function. However, the role of individual PKC isoforms is poorly understood. Biochemical and genetic approaches were used to determine whether PKCh is involved in a IIb b 3 signaling. PKCh was constitutively associated with a IIb b 3 in human and murine platelets. Fibrinogen binding to a IIb b 3 stimulated the association of PKCh with tyrosine kinases Btk and Syk, and tyrosine phosphorylation of PKCh, Btk and the actin regulator, Wiskott-Aldrich syndrome protein (WASP). Mouse platelets deficient in PKCh or Btk failed to spread on fibrinogen. Furthermore, PKCh was required for phosphorylation of WASP-interacting protein on Ser-488, an event that has been linked to WASP activation of the Arp2/3 complex and actin polymerization in lymphocytes. Neither PKCh nor Btk were required for agonist-induced inside-out signaling and fibrinogen binding to a IIb b 3 . Thus, PKCh is a newly identified, essential member of a dynamic outside-in signaling complex that includes Btk and that couples a IIb b 3 to the actin cytoskeleton.

2025, Thrombosis and Haemostasis

complexes in plasma reflect activation of the contact system in vivo. Here, we report the development of radioimmunoassay& (RIAs) for these complexes using a monoclonal antibod¥ (mAb

2025, Vascular Pharmacology

Background: During wound repair, fibrin acts both as a barrier to prevent blood loss and as a temporary matrix for the invasion and ingrowth of endothelial and tissue cells. A wellcontrolled angiogenesis process in the fibrinous exudate matrix is crucial for optimal wound healing. The composition and structure of the fibrin matrix are important determinants of the invasion of endothelial cells and capillary-tube formation into the matrix. Objective: Fibrinogen circulates in a high and low molecular weight form (HMW and LMW, respectively) and the purpose of this study was to investigate how fibrin matrices from these naturally occurring fibrinogen variants influence angiogenesis. Angiogenesis was studied using an in vitro model in which human microvascular endothelial cells (hMVEC) were cultured on three-dimensional fibrin matrices from different fibrinogen forms, and using two in vivo mouse models. Results: The in vitro angiogenesis in an HMW-fibrin matrix shows increased cell and tubular structure ingrowth compared with unfractionated fibrin matrix (median increase 58%, range 46-234%). The ingrowth of tubular structures in an LMW-fibrin matrices is decreased when compared with unfractionated fibrin (median decrease 70%, range 67-100%). Similar results were observed for in vivo angiogenesis. Conclusions: The naturally occurring fibrinogen variants HMW-and LMW-fibrin modulate the angiogenic capacity of endothelial cells in fibrin matrices. The different effects of the molecular weight fibrinogen variants provide further insight in the matrix characteristics in angiogenesis and could possibly be applied in the context of tissue engineering and wound healing.

2025, Journal of Thrombosis and Haemostasis

2025, Thrombosis and Haemostasis

SummaryIn recent decades, evidence has been accumulating showing the important role of urokinase-type plasminogen activator (uPA) in growth, invasion, and metastasis of malignant tumours. The evidence comes from results with animal tumour models and from the observation that a high level of uPA in human tumours is associated with a poor patient prognosis. It therefore initially came as a surprise that a high tumour level of the uPA inhibitor plasminogen activator inhibitor-1 (PAI-1) is also associated with a poor prognosis, the PAI-1 level in fact being one of the most informative biochemical prognostic markers. We review here recent investigations into the possible tumour biological role of PAI-1, performed by animal tumour models, histological examination of human tumours, and new knowledge about the molecular interactions of PAI-1 possibly underlying its tumour biological functions. The exact tumour biological functions of PAI-1 remain uncertain but PAI-1 seems to be multifunctio...

2025, Pathophysiology of Haemostasis and Thrombosis

Activation of prothrombin to thrombin is the key reaction in blood coagulation cascade. We have recently shown that Australian rough scaled snake, Tropidechis carinatus, possesses two parallel prothrombin activator systems. Trocarin D, a venom prothrombin activator produced in the venom gland, plays an offensive role as a toxin, whereas factor X is produced in the liver and plays a role in the hemostatic mechanism. These two proteins are structurally similar and have identical domain architecture. Because of the differences in their physiological roles, and tissue-specific expression, we determined the gene structure of these closely related proteins. Both the genes have eight exons similar to all mammalian factor X genes. All the exon-intron boundaries of these two genes are at the same position and the splice junctions are almost identical. Partial sequencing of the introns shows that they share a very high degree of sequence identity indicating that the gene duplication is a rece...

2025, Journal of Thrombosis and Haemostasis

Megakaryocytes (MKs) expand and differentiate over several days in response to thrombopoietin (Tpo) before releasing innumerable blood platelets. The final steps in platelet assembly and release represent a unique cellular transformation that is orchestrated by a range of transcription factors, signaling molecules, and cytoskeletal elements. Here we review recent advances in the physiology and molecular basis of MK differentiation. Genome-wide approaches, including transcriptional profiling and proteomics, have been used to identify novel platelet products and differentiation markers. The extracellular factors, stromal-derived factor (SDF)-1 chemokine and fibroblast growth factor (FGF)-4 direct MK interactions with the bone marrow stroma and regulate cytokine-independent cell maturation. An abundance of bone marrow MKs induce pathologic states, including excessive bone formation and myelofibrosis, and the basis for these effects is now better appreciated. We review the status of transcription factors that control MK differentiation, with special emphasis on nuclear factor-erythroid 2 (NF-E2) and its two putative target genes, b1-tubulin and 3-b-hydroxysteroid reductase. MKs express steroid receptors and some estrogen ligands, which may constitute an autocrine loop in formation of proplatelets, the cytoplasmic protrusions within which nascent blood platelets are assembled. Finally, we summarize our own studies on cellular and molecular facets of proplatelet formation and place the findings within the context of outstanding questions about mechanisms of thrombopoiesis.

2025, Journal of Thrombosis and Haemostasis

Background: Endothelial von Willebrand factor (VWF) mediates platelet adhesion and acts as a protective chaperone to clotting factor VIII. Rapid release of highly multimerized VWF is particularly effective in promoting hemostasis. To produce this protein, an elaborate biogenesis is required, culminating at the trans-Golgi network (TGN) in storage within secretory granules called Weibel-Palade bodies (WPB). Failure to correctly form these organelles can lead to uncontrolled secretion of low-molecular-weight multimers of VWF. The TGN-associated adaptor AP-1 and its interactors clathrin, aftiphilin and c-synergin are essential to initial WPB formation at the Golgi apparatus, and thus to VWF storage and secretion. Objectives: To identify new proteins implicated in VWF storage and/or secretion. Methods: A genomewide RNA interference (RNAi) screen was performed in the Nematode C. elegans to identify new AP-1 genetic interactors. Results: The small GTPase Rab10 was found to genetically interact with a partial loss of function of AP-1 in C. elegans. We investigated Rab10 in human primary umbilical vein endothelial cells (HUVECs). We report that Rab10 is enriched at the Golgi apparatus, where WPB are formed, and that in cells where Rab10 expression has been suppressed by siRNA, VWF secretion is altered: the amount of rapidly released VWF was significantly reduced. We also found that Rab8A has a similar function. Conclusion: Rab10 and Rab8A are new cytoplasmic factors implicated in WPB biogenesis that play a role in generating granules that can rapidly respond to secretagogue.

2025

We would like to acknowledge our supervisors Professor, Alberto Redaelli, for giving us the possibility to work on this project and Professor Marvin J. Slepian for welcoming us as part of the team. We also would like to thank Silvia Bozzi, PhD, for the support and technical advices she gave us during the work. We would also like to acknowledge the Sarver Heart Centre team, Daniel, Sparky, Allegra, Kaitlyn, Adriana, Yana and Sam for their help and their friendship. A special acknowledgment goes to our families for the opportunity they gave us to follow our dreams and for supporting us during this experience. A kindly thought goes to all our friends, for the lovely time we've spent together and all their support. Finally, we would like to thank each other for supporting, affection, patience and understanding.

2025, Thrombosis and Haemostasis

2025, Journal of Thrombosis and Haemostasis

Background: Apixaban, an oral potent reversible direct inhibitor of activated factor X, has shown promise in the prevention of venous thromboembolism following major orthopedic surgery. We conducted a dose-ranging study in patients with deep vein thrombosis. Methods: Consecutive patients with symptomatic deep vein thrombosis were included and randomized to receive 84-91 days of apixaban 5 mg twicedaily, 10 mg twice-daily, or 20 mg once-daily, or low molecular weight heparin (LMWH) followed by a vitamin K antagonist (VKA). The primary efficacy outcome was the composite of symptomatic recurrent venous thromboembolism and asymptomatic deterioration of bilateral compression ultrasound or perfusion lung scan. The principal safety outcome was the composite of major and clinically relevant, non-major bleeding. Results: The mean age of the 520 included patients was 59 years, and 62% were male. The primary outcome occurred in 17 of the 358 apixaban-treated patients [4.7%, 95% confidence interval (CI) 2.8-7.5%] and in five of the 118 LMWH/VKA-treated patients (4.2%, 95% CI 1.4-9.6%) who were evaluable. The incidence in all three apixaban groups was low and comparable without evidence of a dose response. The principal safety outcome occurred in 28 (7.3%) of the 385 apixaban-treated patients and in 10 (7.9%) of the 126 LMWH/ VKA-treated patients. No dose response for apixaban was observed. Conclusion: These observations warrant further evaluation of apixaban in phase III studies. The attractive fixed-dose regimen of this compound may meet the demand to simplify anticoagulant treatment in patients with established venous thromboembolism.

2025, Thrombosis and Haemostasis

SummaryInsights into hemostasis and thrombosis have historically benefited from the astute diagnosis of human bleeding and thrombotic disorders followed by decades of careful biochemical characterization. This work has set the stage for the development of a number of mouse models of hemostasis and thrombosis generated by gene targeting strategies in the mouse genome. The utility of these models is the in depth analysis that can be performed on the precise molecular interactions that support hemostasis and thrombosis along with efficacy testing of various therapeutic strategies. Already the mouse has proven to be an excellent model of the processes that support hemostasis and thrombosis in the human vasculature. A brief summary of the salient phenotypes from knockout mice missing key platelet receptors is presented, including the glycoprotein (GP) Ib-IX-V and GP IIb/IIIa (αIIb/β3) receptors; the collagen receptors, GP VI and α2/β1; the protease activated receptors (PARs); and the pur...

2025, Journal of Thrombosis and Haemostasis

Background-A signaling pathway is difficult, if not impossible, to elucidate in platelets using only in vivo studies. Likewise, the physiological significance of signaling information obtained exclusively from in vitro observations is unknown. Therefore, both in vitro and in vivo experiments are required to establish the physiological significance of a signaling pathway. Objective-To evaluate the physiological significance of signaling data obtained from botrocetin (bt)/von Willebrand factor (VWF)-stimulated washed platelets. Method-Stable thrombus formation in response to FeCl 3 -induced injury of the mouse carotid artery was used to evaluate the physiological significance of signaling data obtained from bt/VWFstimulated washed platelets. Results-Syk, PLCγ2, Gαq and P2Y12, but not LAT, were found either to be required for or to affect stable thrombus formation. Prior in vitro studies had demonstrated that LAT is not required for bt/VWF-induced platelet aggregation in the presence of exogenous fibrinogen. These data provide the first demonstration of the in vivo role for these signaling molecules in GPIb-dependent/initiated signal transduction and are consistent with the signaling pathway deduced from in vitro studies of bt/VWF-stimulated washed platelets using metabolic inhibitors and knockout mice. The broad agreement between the in vitro and the in vivo results establish that bt/ VWF stimulation of washed platelets can provide physiologically significant glycoprotein Ibdependent/initiated signaling data.

2025, SUPPLEMENTARY ABSTRACTS

A 52 year old female patient with a severe bleeding tendency since the age of two was studied. Her history revealed recurrent petechial bleedings, two severe postoperative haemorrhagic episodes and intensivemenstrual bleedings which... more

2025

Bruins, Peter Changes in the inflammatory response during and after cardiac surgery/ Peter Bruins Thesis University of Amsterdam. -With ref. -Met samenvatting in het Nederlands. ISBN 90-9013599-5 Cover: Coverdesign by Inge Kos, Medische fotografie en illustratie, AMC, Amsterdam. Slide showing co-localization of CRP and C3d in infarcted myocardium, immunohistochemical double staining using monoclonal antibodies 5G4 (brown) for CRP and C3-15 (blue) for complement (by H.W.