Journal of Thrombosis and Haemostasis最新文献

Background: Inherited platelet diseases are bleeding disorders characterized by either defects in platelet count or platelet function, the latter being less common and very heterogeneous. Numerous gene variants associated with abnormal receptors, granules, and signaling pathways have been reported. Despite significant advancements in our understanding, many patients still lack a precise diagnosis.

Objectives: To identify the genetic basis of a novel mild bleeding syndrome in a family exhibiting a selective defect of platelet aggregation.

Methods: Our study included 6 family members across 3 generations who displayed reduced platelet aggregation in response to adenosine diphosphate, protease-activated receptor 1-activating peptide, arachidonic acid, and epinephrine but not collagen. Platelet morphology, granule content, and expression of major surface glycoproteins were all found to be normal. Whole exome sequencing was performed for affected and nonaffected family members.

Results: We identified RGS18, which encodes the regulator of G protein signaling (RGS) 18, as a candidate gene for the platelet function defect observed in this family. The RGS18 protein serves as a crucial negative regulator of G protein-coupled receptor signaling and coordinates the signaling pathways of natural platelet inhibitors. The heterozygous RGS18 c.643C>T, p.Arg215∗ variant was found to cosegregate among all 6 affected subjects.

Conclusion: Truncation at Arg215 removes the S216 and S218 phosphorylation sites, which are crucial regulatory domains for RGS18 activation. The impaired platelet function is thought to arise from excessive platelet downregulation due to constitutive activation of RGS18, resulting from a loss of association of the truncated form with the 14-3-3 protein.

Background: Managing older patients with acute pulmonary embolism (PE) is challenging due to their underrepresentation in clinical trials, comorbidities, and increased complication risk.

Objectives: To evaluate risk assessment and management outcomes in older patients with PE focusing on home and reperfusion treatment.

Methods: A retrospective analysis was conducted on patients aged 70 years or older diagnosed with acute PE at an academic medical center (2015-2022).

Results: In total, 242 patients with a mean age of 77 years were included. All 59 patients with negative Hestia criteria were discharged ≤24 hours, and in total, 81 patients (35%) received home treatment. Among these 14-day mortality and recurrent venous thromboembolism were 0% and major bleeding occurred in 1.3% (1 patient, 95% CI: 0.11-6.1). European Society of Cardiology risk classification showed 9 low-risk (3.9%), 199 intermediate-risk (87%), and 20 high-risk (8.8) patients with PE. In 5 of the 20 high-risk patients, hypotension was mainly caused by another condition, that is, sepsis. Eight high-risk patients received reperfusion therapy. The 14-day mortality rate was 51% in high-risk patients (95% CI: 27-71); 5 of 8 patients receiving reperfusion treatment died within 5 days. Patients with an Acute Presenting Older Patient score of ≥45% had higher 14-day mortality (28%; 95% CI: 12-46) compared with <45% (3.2%; 95% CI: 0.85-8.3; hazard ratios: 10.2; 95% CI: 2.6-39).

Conclusion: Selecting for home treatment using Hestia criteria was safe for older patients with PE in our cohort. Mortality in the high-risk group was high also when receiving reperfusion treatment. The European Society of Cardiology risk classification and Acute Presenting Older Patient score identified patients at higher mortality risk, suggesting their potential utility in clinical decision-making.

Background: Deep vein thrombosis (DVT) is a major cause of morbidity and mortality globally. While its pathophysiology is complex, increasing evidence suggests a more prominent role for platelets than previously suspected. Genetic deletion of Ral GTPases, RalA and RalB, conditionally in mouse platelets (RalAB DKO), results in a near complete defect in P-selectin externalisation upon activation, while other platelet activation responses and arterial thrombosis are preserved.

Objective: Given the critical role of P-selectin in mediating platelet-neutrophil interaction and thromboinflammation, we sought to investigate whether platelet Rals would also play critical roles in venous thrombosis, a thromboinflammatory disease, using RalAB DKO mice.

Methods: DVT was induced by surgical partial ligation of the caudal (inferior) vena cava for 24-h or 48-h before venous thrombi were assessed by histology and immunofluorescence microscopy.

Results: RalAB DKO mice show a reduction in venous thrombus formation after 24-h, and near complete ablation of venous thrombosis by 48-h post IVC ligation. Immunofluorescence microscopy revealed that cross sections of thrombi from wildtype mice consist of an organised scaffolded structure of platelets surrounding leukocytes/neutrophils producing NETs to stabilize and propagate the thrombus. This organised structure was absent in platelet-specific conditional RalAB DKO thrombi. In vitro analysis of platelet-mediated NET formation was also significantly reduced when platelets lacked RalAB or when platelets were treated with the Ral inhibitor RBC8.

Conclusion: We identify platelet Rals as novel, potentially critical regulators of venous thrombus stability, through their ability to regulate neutrophil NET formation via platelet P-selectin.

Background: Acute large vessel occlusion (LVO) stroke is highly prevalent and severe. Despite thrombolytic therapy, many patients experience substantial complications. Understanding the origins, constituents, and pathologic processes involved in thrombus formation in acute intracranial large artery occlusion is crucial.

Objectives: To identify the characteristics of insoluble proteins from different sources of cerebral thrombus.

Methods: This study included 13 patients with cardiogenic embolic (CE) thrombus and 15 with large artery atherosclerotic (LAA) thrombus. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry were used to analyze insoluble proteins in thrombi. Bioinformatics analyses explored differential proteins and associated functional pathways. Least absolute shrinkage and selection operator and random forest identified biomarkers for diagnosing thrombus sources, validated by parallel reaction monitoring.

Results: We constructed an insoluble protein atlas of cerebral thrombi, identifying 6975 insoluble proteins, including 143 extracellular matrix (ECM)-related proteins. The enrichment pathways considerably varied between thrombi from different sources. Inflammation-related pathways, such as acute inflammatory response, along with ECM-related pathways such as laminin interactions, were notably upregulated in LAA compared with CE. Additionally, 2 biomarkers (IDH2 and HSPG2) exhibited strong diagnostic performance (area under the curve = 1) and robustness.

Conclusion: In the insoluble proteomics of thrombus, we highlighted the crucial roles of immune responses and ECM proteins in thrombus formation, providing new insights into its mechanisms and potential drug development. Additionally, we identified 2 biomarkers that offer new methods for determining thrombus sources in patients with LVO.

Background: Non-immunogenic staphylokinase is a modified recombinant staphylokinase with low immunogenicity, high thrombolytic activity, and fibrin selectivity.

Objectives: To assess the safety and efficacy of a single intravenous bolus of non-immunogenic staphylokinase compared with those of alteplase in patients with massive pulmonary embolism and hemodynamic instability.

Methods: A randomized, open-label, multicenter, parallel-group, non-inferiority trial, the FORPE (FORtelyzin Pulmionary Embolism), was conducted in Russia. A total of 310 patients aged 18 years and older with computed tomography pulmonary angiography confirmed diagnosis of massive pulmonary embolism and right ventricular dysfunction were included. The patients were randomly assigned to receive either non-immunogenic staphylokinase (15 mg) or alteplase (100 mg), both administered intravenously. The primary efficacy endpoint was death from all causes within 7 days of randomization.

Results: A total of 155 patients were randomly assigned to receive non-immunogenic staphylokinase, and 155 received alteplase. In the non-immunogenic staphylokinase group, the primary efficacy endpoint was 2% in the intention-to-treat population, while in the alteplase group, it was 3% (odds ratio, 0.75; 95% CI, 0.11-4.49; P = 1.00). The difference in the primary efficacy endpoint was 0.6% (95% CI, -2.8% to 4.0%). Thus, the lower limit of the 95% CI did not cross the margin of non-inferiority. No cases of major bleeding were recorded in the non-immunogenic staphylokinase group, whereas there were 5 cases of major bleeding (3%; P = .09) in the alteplase group.

Conclusion: Non-immunogenic staphylokinase was non-inferior to alteplase in patients with massive pulmonary embolism. Future observational studies are needed to assess its safety and efficacy.

Background: Myocardial ischemia-reperfusion (MI/R) injury tends to affect cardiac function and leads to poor patient prognosis, and there is still no effectively targeted drug to develop anti-von Willebrand factor (VWF) aptamer in acute coronary heart disease. However, the newly anti-VWF aptamer BT200 is applied not only for stroke and hemophilia but also for antithrombolism function in clinical development. The role of BT200 in acute myocardial injury during MI/R is still unknown.

Objectives: To investigate the cardioprotective effect of aptamer BT200 in a mouse model of MI/R.

Methods: C57BL/6 mice were subjected to 30-minute ischemia and 24-hour reperfusion to establish MI/R model. Mice were treated with intravenous injection of cy3-labeled BT200 and were observed by an in vivo imaging system at different time points. Then, mice were sampled and evaluated by echocardiography, Evans triphenyltetrazolium chloride staining, histopathologic, western blotting, and real-time quantitative polymerase chain reaction assays to detect cardiac injury and inflammation response after 24-hour reperfusion.

Results: BT200 aptamer can enter and infiltrate into the ischemic myocardium after 24-hour reperfusion. BT200 was shown to inhibit VWF A1 activity and prolong bleeding time in MI/R mice. Moreover, BT200-treated mice had a significant reduction in infarct size and an improvement in cardiac function post-MI/R. BT200 treatment can also alleviate MI/R-induced microvascular obstruction, inflammation response, and cardiomyocyte apoptosis.

Conclusion: Pharmacologic targeting of VWF with BT200 alleviates acute MI/R injury in a murine model and may be a novel therapy strategy for acute myocardial infarction.

Background: The vascular endothelial cell (EC) monolayer plays a crucial part in maintaining hemostasis. An extensive array of G protein-coupled receptors allows ECs to dynamically act on key hemostatic stimuli such as thrombin and histamine. The impact of these individual stimuli on EC signal transduction has been the subject of various studies, but insight into discordant and concordant EC signaling between different G protein-coupled receptors remains limited.

Objectives: To elucidate histamine and protease-activated receptor (PAR1-4) signaling cascades in ECs, discern overlapping and diverging regulation between these stimuli and their effect on the EC monolayer.

Methods: We employed stable isotope labeling by amino acids in cell culture mass spectrometry-based phosphoproteomics on in vitro cultured blood outgrowth ECs stimulated with histamine and different PAR1 to 4 peptides. We investigated key phosphosites through immuno(fluorescence) staining and determined effects on barrier function through transendothelial resistance assays.

Results: EC histamine activation initiated an extensive (kinase) signaling network (including MAPK3, STAT3, and CTNND1). PAR1 and PAR2 receptors induced highly similar signaling cascades, whereas PAR3 and PAR4 induced minimal phospho-regulation. Integration of all applied stimuli indicated uniquely activated proteins between both stimuli, as well as a general overlapping activation of cell junction and actin cytoskeletal proteins.

Conclusion: We provide an integrative phosphoproteomic analysis of histamine and PAR agonists in the endothelium that highlights the endothelial response programs that are at the basis of regulating hemostasis.

Background: Intravenous thrombolysis (IVT) using recombinant tissue plasminogen activator prior to endovascular thrombectomy treatment (EVT) failed to improve treatment effect in acute ischemic stroke (AIS) patients compared with EVT alone.

Objectives: We investigated whether primary and secondary hemostasis biomarkers are associated with the effect of intravenous thrombolytics on clinical and radiological outcomes after EVT.

Methods: In the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN)-NO IV, AIS patients were randomized to receive IVT plus EVT or EVT alone. We measured hemostatic biomarkers before and 24 hours postreperfusion to determine changes in biomarkers and the association of the biomarkers with short term stroke severity on National Institutes of Health Stroke Scale score, long-term functional outcome (modified Rankin scale [mRS] score), post-EVT extended Thrombolysis in Cerebral Infarction score, and final infarct size.

Results: This substudy included 214 of the 539 AIS patients who underwent IVT + EVT (n = 108/266) or EVT alone (n = 106/273). In the EVT group, low soluble glycoprotein VI (sGPVI) and high factor (F)VIII levels before treatment were associated with severe National Institutes of Health Stroke Scale score at 24 hours and poor mRS score at 90 days posttreatment, respectively. Also, in this group, sGPVI levels 24 hours after treatment were negatively associated with final infarct size. In the IVT + EVT group, high fibrinogen before treatment was associated with good extended Thrombolysis in Cerebral Infarction score, and low a disintegrin and metalloprotease with thrombospondin motif repeats 13 activity 24 hours posttreatment was associated with an unfavorable mRS score at 90 days.

Conclusion: Our findings suggest that patients with high FVIII and fibrinogen and low sGPVI levels might be the most suitable candidates for IVT + EVT and that patients with low a disintegrin and metalloprotease with thrombospondin motif repeats 13 activity might be suitable for EVT alone.

Background: Concerns have been raised regarding the updated Beers Criteria that recommended avoiding rivaroxaban use for long-term treatment of older adults with nonvalvular atrial fibrillation (AF).

Objectives: We sought to compare the effectiveness and safety of rivaroxaban with oral anticoagulants in older adults with nonvalvular AF.

Methods: We used an administrative healthcare database and included adults with AF aged ≥65 years who were new users of rivaroxaban or the comparators. We created 3 pairwise comparisons: rivaroxaban vs warfarin; rivaroxaban vs dabigatran; and rivaroxaban vs apixaban. Study outcomes included stroke or systemic embolism (effectiveness) and gastrointestinal or intracranial bleeding (safety). In the propensity score-matched sample, we used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% CIs.

Results: In the matched cohorts, use of rivaroxaban (vs warfarin) increased risk of bleeding (HR, 1.13; 95% CI, 1.03-1.23) with no difference in ischemic stroke or systemic embolism (HR, 0.90; 95% CI, 0.79-1.02); use of rivaroxaban (vs dabigatran) increased risk of bleeding (HR, 1.18; 95% CI, 1.03-1.35) with no difference in ischemic stroke and systemic embolism (HR, 1.00; 95% CI, 0.83-1.22); and use of rivaroxaban (vs apixaban) increased risk of stroke and systemic embolism (HR, 1.23; 95% CI, 1.08-1.40) and bleeding (HR, 1.60; 95% CI, 1.45-1.76).

Conclusion: In this comparative effectiveness and safety study of older adults with nonvalvular AF, use of rivaroxaban was associated with a significantly increased risk of ischemic stroke and systemic embolism compared with apixaban and bleeding compared with warfarin, dabigatran, and apixaban. Our findings may inform anticoagulant selection in older adults with nonvalvular AF.

Background: Limited language proficiency is an established barrier to research participation among racialized populations. While prior studies have highlighted the underrepresentation of racialized populations in venous thromboembolism (VTE) research, the impact of limited language proficiency as a reason for nonconsent among eligible patients is unknown.

Objectives: To determine the impact of language barrier as the primary reason for VTE research non-participation.

Methods: We reviewed all prospective VTE studies conducted at a research-intensive academic thrombosis research program in Canada between 2014 and 2024. Studies with screening logs that systematically and consecutively captured eligibility assessment and reasons for nonconsent were included. Primary outcome was nonconsent of a screen-eligible patient due to limited language proficiency as the reported reason. We derived pooled estimates of nonconsent due to limited language proficiency as a proportion of consented participants and determined subgroup rates by phase of VTE management, associated medical conditions, and recruitment settings.

Results: Screening logs of 28 studies with 22 057 screening events, 8317 screen-eligible patients, and 3320 consented participants were included. For every 100 consented participants, 3.2 (95% CI, 2.0-5.3) screen-eligible individuals were unable to provide consent due to limited language proficiency. Rates of nonconsent were highest in studies involving cancer (5.6 per 100 participants; 95% CI, 2.9-10.4) and in studies recruiting patients from ambulatory settings outside of the thrombosis clinic (10.8 per 100 participants; 95% CI, 4.8-22.6).

Conclusion: Language proficiency is a key barrier to VTE research participation. Urgent implementation of targeted interventions aimed at mitigating linguistic barriers is essential to ensure equitable opportunities for VTE research participation for racialized patients disproportionately affected by language proficiency.