Journal of Thrombosis and Haemostasis最新文献

Antiphospholipid syndrome is an autoimmune disorder characterized by the development of spontaneous venous, arterial, or microvascular thrombosis and/or pregnancy-related complications (e.g. miscarriages, fetal loss) in the presence of persistent antiphospholipid antibodies (aPL). Current state-of-the-art treatment consists of indefinite anticoagulation with vitamin K antagonists to prevent recurrence of thrombotic events. This, however, only represents a symptom-control oriented treatment approach. Until today, no curative option eradicating aPL permanently or addressing the underlying pathomechanism has been established. Here, we report the case of a woman with systemic lupus erythematosus and antiphospholipid syndrome with triple aPL-positivity who developed recurrent deep veinous thrombosis. After receiving CAR T-Cell therapy for aggressive B-Cell lymphoma, sustained eradication of all three aPL subtypes was observed, suggesting a promising role of immunotherapies targeting anti-CD19 for the treatment of pro-thrombotic autoimmune disorders.

Background: Whether primary or just as a complication from the progression of pulmonary arterial hypertension (PAH), thrombosis seems to be an important player in this condition. The crosstalk between red blood cells (RBCs) and pulmonary microvascular endothelial cells (PMVECs) and their role in PAH remain undefined.

Objectives: The goals of this study were to assess the role of RBC-PMVEC interaction in microvascular thrombosis and thrombotic vascular remodeling under hypoxic conditions.

Methods: We established an in vitro hypoxic coincubation model of RBC and PMVEC as well as a hypoxic mouse model. We investigated erythrophagocytosis (EP), ferroptosis, thrombosis tendency, and pulmonary hemodynamics in experimental PAH.

Results: Increased EP in PMVEC triggered ferroptosis, enhanced procoagulant activity, and exacerbated vessel remodeling under hypoxic conditions. In the PAH mouse model induced by chronic hypoxia, EP-induced ferroptosis followed by upregulated TMEM16F led to a high tendency of thrombus formation and thrombotic vascular remodeling. Inhibition of ferroptosis or silencing of TMEM16F could alleviate hypercoagulable phenotype, reverse right ventricular systolic pressure, right ventricular hypertrophy index, and remodeling of pulmonary vessels.

Conclusion: These results illustrate the pathogenic RBC-PMVEC interactions in PAH. Inhibition EP, ferroptosis, or TMEM16F could be a novel therapeutic target to prevent PAH development and thrombotic complications.

Background: Despite appropriate treatment, up to 50% of patients with proximal deep vein thrombosis will develop postthrombotic syndrome (PTS). Once PTS occurs, there is no specific treatment, and some patients constantly experience intolerable symptoms. Hence, prevention of PTS is important.

Objectives: To characterize vein wall remodeling after thrombus and investigate the effects of antiproliferative agent on postthrombotic vein wall remodeling in murine and human subjects.

Methods: Features of postthrombotic vein wall remodeling in murine and human subjects were characterized using imaging and histologic examinations. Paclitaxel-loaded hydrogels were used to assess the effects of antiproliferative agent on the remodeling in murine model. Based on the abovementioned results, a pilot study was conducted to assess the effects of paclitaxel-coated balloon dilation in patients with severe PTS experiencing intolerable symptoms. The control cohort was obtained by 1:1 propensity score matching from a prospective database.

Results: Structural and functional alterations in postthrombotic vein wall were verified by imaging and histologic examinations, and predominant active α-smooth muscle actin-positive cells and fibroblast-specific protein 1-positive cells proliferation was observed. In the murine model, the application of paclitaxel-loaded hydrogels inhibited the remodeling. In the pilot clinical study, patients receiving drug-coated balloon demonstrated benefits in Villalta scores and venous clinical severity scores compared with those not receiving drug-coated balloon, and no severe adverse events were reported except for thrombosis recurrence.

Conclusion: Cell proliferation plays an important role in postthrombotic vein wall remodeling. Inhibition of cell proliferation inhibits the remodeling in murine model and may reduce signs and symptoms in patients with severe PTS.

Background: Type 2B von Willebrand disease (VWD) is a bleeding disorder caused by gain-of-function variants in the VWF gene. The laboratory and clinical phenotype of type 2B VWD is heterogeneous.

Objectives: We investigated associations between genotype and phenotype over a median of 16 years follow-up in a large cohort of well-characterized patients.

Methods: We included 64 genetically confirmed type 2B VWD patients from the national multicenter "Willebrand in the Netherlands" study and retrospectively collected clinical and laboratory data from electronic patient records. We analyzed associations between genotype and thrombocytopenia, bleeding phenotype, and events leading to endothelial activation and von Willebrand factor (VWF) secretion, including surgery, desmopressin administration, pregnancy, and delivery.

Results: Thrombocytopenia manifested in 67.2% of patients, with varying occurrences between genetic variants (p.Arg1306Trp: 75.0%, p.Arg1308Cys: 58.3%). The most important determinant of thrombocytopenia was the p.Arg1306Trp VWF variant (odds ratio, 25.1). Platelet counts strongly varied over time and were continuously <150 × 10⁹/L in 37.5% of patients with p.Arg1306Trp vs 8.3% in p.Arg1308Cys. In our analysis, endothelial activation was not an independent determinant (odds ratio, 1.3) for thrombocytopenia occurrence. No association was found between thrombocytopenia and cumulative bleeding scores or annual bleeding rates. Four women showed declining platelet counts in all full-term pregnancies (n = 8) during the third trimester with a sharp decrease in the week before delivery. Postpartum hemorrhage, defined as >500 mL estimated blood loss at delivery, occurred in 5 of 8 deliveries, despite prophylactic treatment with VWF concentrates.

Conclusion: This study reveals a strong association between VWF variant p.Arg1306Trp and thrombocytopenia in type 2B VWD patients.

Background: The incidence, risk factors, and outcomes of venous thromboembolism (VTE) in patients with chronic lymphocytic leukemia (CLL) and monoclonal B-cell lymphocytosis (MBL) are not well described.

Objectives: We aimed to determine the clinical characteristics, risk factors, and outcomes of incident VTE in patients with newly diagnosed MBL/CLL and compare the incidence to the age- and sex-matched general population.

Methods: Using the Mayo Clinic CLL Database, we identified 946 patients with newly diagnosed MBL/CLL between 1998 and 2021. Incidence of VTE was identified by querying the electronic health record for VTE-specific International Classification of Diseases-9 and -10 codes and reviewing results of radiographic studies.

Results: Eighty patients developed VTE. The incidence of VTE in patients with newly diagnosed MBL/CLL was ∼1% per year. In multivariable analyses, prior history of VTE (hazard ratio [HR]: 5.33; 95% CI: 1.93-14.68, P = .001) and high/very high-risk CLL-International Prognostic Index score (HR: 2.63; 95% CI: 1.31-5.26; P = .006) were associated with an increased risk of VTE; receipt of CLL treatment or occurrence of nonhematologic malignancy was not. Development of VTE was associated with shorter overall survival (HR: 1.82, 95% CI: 1.30-2.55) after adjusting for age, sex, prior history of VTE, and Rai stage. The age- and sex-adjusted VTE incidence rate for patients with MBL/CLL and no prior history of VTE (n = 904) was 1254 per 100 000 person-years compared with 204 per 100 000 person-years in the general population, reflecting a 5.9-fold increase.

Conclusion: Our study demonstrates a 6-fold increased risk of VTE in patients with MBL/CLL compared with the age- and sex-matched general population.

Background: Platelets are an essential component of hemorrhage control and management, and engineering platelets to express therapeutic proteins could expand their use as a cell therapy. Genetically engineered platelets can be achieved by modifying the platelet precursor cells, megakaryocytes (MKs). Current strategies include transfecting MK progenitors ex vivo with viral vectors harboring lineage-driven transgenes and inducing the production of in vitro modified platelets. The use of viruses, however, poses challenges in clinical implementation, and no methods currently exist to genetically modify MKs with nonviral techniques. Lipid nanoparticles (LNPs) are a nonviral delivery system that could enable a facile strategy to modify MKs with a variety of nucleic acid payloads.

Objectives: To investigate whether LNPs can transfect cultured hematopoietic stem/progenitor cell-derived MKs to express exogenous proteins and induce functional changes.

Methods: MK and MK progenitors differentiated from cord blood-derived hematopoietic stem/progenitor cells were treated with LNP formulations containing messenger RNA and resembling the clinically approved LNP formulations. Transfection efficiency was assessed through flow cytometry by expression of enhanced green fluorescent protein. Functional changes to the MKs were assessed through rotational thromboelastometry by expression of exogenous coagulation factor (F)VII, a representative physiologically relevant protein.

Results: LNPs enabled transfection efficiencies of 99% in MKs and did not impair MK maturation, viability, and morphology. MKs engineered to express exogenous FVII decreased clotting time in FVII-deficient plasma following clot initiation.

Conclusion: This approach provides an easy-to-use modular platform to genetically modify MK and MK progenitors, which can be potentially extended to producing genetically modified cultured platelets.

Introduction: Despite rapid advances in liquid biopsy for circulating tumor DNA (ctDNA), its prognostic value for venous thromboembolism (VTE) in patients with cancer is underexplored, particularly in underserved and minoritized populations.

Methods: We analyzed data from 1,038 cancer patients who underwent ctDNA measurement for oncologic care at a large safety-net hospital system in the US. We investigated the association between ctDNA and VTE after adjusting for cancer type, stage, treatment, and time from initial diagnosis using Fine-Gray models. We further assessed the discrimination of the genetic, clinical-only, and combined models using the area under the time-dependent receiver operating characteristic curve (AUC).

Results: The presence of pathogenic ctDNA was independently associated with VTE after adjusting for clinical variables. Independent of tumor type, the number of pathogenic ctDNA mutations was predictive of future VTE risk (adjusted subdistribution hazard ratio 2.75, 1.94, and 1.38 for ≥3, 2, and 1 pathogenic mutation, respectively, compared to none; p<0.0001). The association was primarily driven by mutations in KRAS, PTEN, CDKN2A, NF1, and EGFR genes. Compared to the clinical-only model (AUC 0.71, 95% CI 0.64-0.76), the combined clinical and ctDNA model had a numerically higher time-dependent AUC (AUC 0.74, 95% CI 0.67-0.80).

Conclusions: CtDNA testing may serve as an adjunctive tool to clinical risk assessment models in cancer patients to improve personalized VTE risk assessment and management.

In the last couple of decades, numerous investigations have shed considerable light on how precisely factor (F)VIIa mediates the initiation of blood coagulation upon association with its cofactor, tissue factor (TF). The role of the cofactor in this process is indispensable under physiological conditions, serving as a membrane-tethering allosteric activator of FVIIa also interacting with substrates (eg, FX). Available evidence reveals the induction and manifestation of complex allostery within FVIIa when stimulated by TF, involving at least 2 connected pathways spanning the interactive interface of the FVIIa-TF complex and the functional segments of FVIIa. Carefully designed FVIIa variants demonstrate corresponding modulations of their properties and response to TF-triggered allostery and activation. In addition, antibodies can stimulate FVIIa activity in both similar and distinctly different ways compared to that employed by TF. The mechanistic insights obtained through basic biochemical investigations have been validated through select engineered FVIIa constructs which, even in vivo, demonstrate beneficial, proof-of-concept effects. Altogether, we have recently gained unprecedented knowledge about and control over FVIIa allostery, enabling us to influence FVIIa activity in advanced manners and in a desired direction. Here, we summarize our current understanding of the allosteric activation of FVIIa ending up with some prospects of future investigations.

Background: Little information regarding the management of invasive procedures in people with hemophilia B (HB) after undergoing gene therapy is available. Here, we report the management of invasive procedures in people with severe or moderately severe HB who had previously been treated with etranacogene dezaparvovec in the phase 2b and phase 3 Health Outcomes with Padua Gene; Evaluation in Hemophilia B clinical trials (NCT03489291 and NCT03569891).

Objectives: The objective of this study was to describe the use of exogenous FIX, endogenous FIX activity prior to invasive procedures, and peri- and postoperative bleeds in participants who underwent invasive procedures after receiving etranacogene dezaparvovec gene therapy.

Methods: This retrospective analysis included invasive procedures performed within 3 and 2 years following a single infusion of 2 × 10¹³ gc/kg of etranacogene dezaparvovec in participants in the phase 2b and Health Outcomes with Padua Gene; Evaluation in Hemophilia B trials, respectively. Data for factor (F)IX dosing, duration of postoperative FIX use, FIX activity prior to invasive procedures, and postoperative bleeds were collected and analyzed.

Results: The analysis included 64 procedures in 29 participants: 9 major surgeries, 24 minor surgeries, 11 endoscopies, 3 endoscopies with biopsy/polypectomy, and 17 dental procedures. Uncontaminated endogenous FIX activity corresponded to mild hemophilia or normal levels prior to 98% of all procedures, with a median endogenous FIX activity of 43.8 IU/dL (range, 3.1-113 IU/dL). All major surgeries were managed with exogenous FIX, 67% with ≤4 days of FIX infusion. Most minor surgeries (88%), endoscopies (82%), and dental procedures (94%) were managed with no or a single FIX infusion. Postoperative bleeds occurred after 1 minor surgery and 4 dental procedures. There were no symptomatic thrombotic events or FIX inhibitor developments.

Conclusion: Etranacogene dezaparvovec has the potential to facilitate perioperative management in people with HB by reducing the need for perioperative exogenous FIX and its associated risks.

Background: The functions of critical platelet proteins are controlled by thiol-disulfide exchanges, which are mediated by the protein disulfide isomerase (PDI) family. It has been shown that some PDI family members are important in platelet activation and thrombosis with distinct functions. TMX4, a membrane-type PDI family member, is expressed in platelets, but whether it has a role in platelet activation remains unknown.

Objectives: To determine the role of TMX4 in platelet activation and thrombosis.

Methods: The phenotypes of TMX4-deficient mice were evaluated in tail bleeding time assay and laser-induced and FeCl₃-induced arterial injury models. The functions of TMX4 in platelets were assessed in vitro using TMX4-null platelets, recombinant TMX4 protein, and anti-TMX4 antibody.

Results: Compared with the control mice, Tie2-Cre/TMX4^fl/fl mice deficient of hematopoietic and endothelial TMX4 exhibited prolonged tail bleeding times and reduced platelet thrombus formation. Pf4-Cre/TMX4^fl/fl mice deficient of platelet TMX4 also had prolonged tail bleeding times and decreased thrombus formation, which was rescued by injection of recombinant TMX4 protein. Consistently, TMX4 deficiency inhibited platelet aggregation, integrin αIIbβ3 activation, P-selectin expression, phosphatidylserine exposure, and thrombin generation, without affecting tyrosine phosphorylation of intracellular signaling molecules Syk, LAT, PLCγ2 and calcium mobilization. Recombinant TMX4 protein enhanced platelet aggregation and reduced integrin αIIbβ3 disulfide bonds, and TMX4 deficiency decreased free thiols of integrin αIIbβ3, consistent with a potent reductase activity of TMX4. In contrast, an inactive TMX4 protein and a specific anti-TMX4 antibody inhibited platelet aggregation.

Conclusion: TMX4 is a novel PDI family member that enhances platelet activation and thrombosis.