Journal of Thrombosis and Haemostasis最新文献

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.

Background: Platelets are critical for thrombosis and hemostasis. The THPO-MPL pathway is the primary pathway for generating thrombocytes. Dysregulation of thrombopoiesis results in platelet formation and/or function-related disorders, such as thrombocytopenia. Paclitaxel is an extensively utilized chemotherapeutic agent and its activity may be related to platelets, but the effect of paclitaxel on thrombocytopoiesis warrants comprehensive exploration.

Objectives: We focused on identifying factors that regulate thrombocyte production and elucidating paclitaxel's regulatory mechanisms on thrombocytopoiesis, with a particular emphasis on discovering mechanisms that bypass THPO-MPL pathways.

Methods: We performed drug screenings using the Tg(mpl:eGFP) zebrafish model in vivo to identify Food and Drug Administration-approved compounds capable of boosting thrombocyte production. An injury experiment was used to evaluate thrombocyte function. Bromodeoxyuridine assays, terminal deoxynucleotidyl transferase dUTP nick-end labeling, and RNA sequencing analyses were performed to explore cytological and molecular mechanisms. Routine blood testing and flow cytometry were used to analyze mouse phenotypes.

Results: We found that paclitaxel expands thrombocytes by accelerating the proliferation of thrombocytic lineage cells in zebrafish and elevates platelet levels in mice. This effect occurs by bypassing the thrombopoietin receptor (Mpl). We found that paclitaxel promotes thrombopoiesis, potentially involving the JAK2-ERK1/2 MAPK signaling cascade, a pathway integral to MPL and other regulators. Our results further demonstrate that ERK1/2 is at least partially downstream of JAK2 in paclitaxel-induced thrombopoiesis.

Conclusion: Paclitaxel could promote thrombopoiesis by bypassing Mpl but presumably via the JAK2-ERK1/2 MAPK pathways. It will aid in understanding the relationship between paclitaxel and platelets clinically, and paclitaxel may have potential value for safeguarding platelets and improving thrombocytosis in related diseases.

Background: Patients with metabolic dysfunction-associated steatohepatitis (MASH) are at an increased risk of developing venous thromboembolic events, including deep vein thrombosis (DVT). To date, the study of DVT in MASH has been hampered by the lack of reliable models that mimic the pathologic aspects of human disease.

Objectives: To evaluate DVT severity and hypercoagulability in murine and human MASH.

Methods: Transcriptional changes in the liver, plasma markers of coagulation, and DVT severity were evaluated in mice fed a standard chow diet or a high-fructose, high-fat, and high-cholesterol MASH diet for 24 weeks. Plasma analyses of coagulation markers and thrombin generation assays were performed in a well-characterized cohort of patients with or without MASH.

Results: Mice fed the MASH diet developed steatohepatitis and fibrosis, mimicking human MASH. Liver RNA sequencing revealed a significant upregulation of pathways related to inflammation and coagulation concomitant with increased levels of plasma coagulation markers including increased prothrombin fragment 1+2, thrombin-antithrombin complex, plasminogen activator inhibitor-1 levels, and endothelin 1. MASH exacerbated DVT severity in mice, as evidenced by increased thrombus weight and higher thrombosis incidence (15/15 vs 11/15 in controls, P = .0317). Higher endothelin 1 release and increased apoptosis were found in endothelial cells stimulated with supernatants of palmitate-stimulated HepG2 cells. Patients with MASH exhibited increased levels of plasma coagulation markers and delayed thrombin generation.

Conclusion: We report enhanced DVT severity and hypercoagulability, both in murine and human MASH. Our model of MASH-DVT can facilitate a better understanding of the fundamental mechanisms leading to increased venous thromboembolic events in patients with MASH.

Background: A considerable number of patients with chronic thromboembolic pulmonary hypertension (CTEPH) lack a history of venous thromboembolism (VTE).

Objectives: We aimed to examine the annual incidence and prevalence of CTEPH in Denmark and to compare the rates of VTE, bleeding, and mortality between CTEPH patients with and without a history of VTE.

Methods: The Danish National Patient Registry covering all Danish hospitals was used to identify all CTEPH cases between 2009 and 2018, based on combinations of discharge diagnoses using International Classification of Diseases, 10th Revision codes for CTEPH and relevant diagnostic and/or therapeutic interventions. Incidence rates of CTEPH per 100 000 person-years, rates of VTE and bleeding, and 5-year survival estimates were calculated.

Results: In total, 509 CTEPH patients were identified, of whom 82% had a history of VTE. The yearly incidence rate of CTEPH was 0.5 to 0.8 per 100 000 person-years during the study period. Patients with a history of VTE experienced a 2.5-fold rate of VTE compared with those without prior VTE (2571 vs 980 per 100 000 person-years), while the rate of bleeding events was lower (5008 vs 7139 per 100 000 person-years). The 5-year survival of CTEPH patients with a VTE history was 65% (95% CI, 58%-71%) compared with 45% (95% CI, 31%-58%) in patients without a history of VTE.

Conclusion: The Danish incidence rate of CTEPH was comparable with that of other European countries. We identified notable differences in the prognosis of patients with CTEPH with or without a history of VTE. These findings may support generation of hypotheses regarding the pathophysiology of CTEPH and inform current patient care.