Journal of Thrombosis and Haemostasis最新文献

Background: Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by dysregulation of the complement system due to genetic mutations and polymorphisms in complement activators and regulators. In Japan, C3 is the gene most frequently implicated in aHUS, with approximately three-quarters of the mutations reported for C3 corresponding to p.Ile1157Thr (p.I1157T). Patients with the C3 p.I1157T mutation are notable for their favorable prognosis despite the high frequency of aHUS relapse compared with other C3 mutations; however, some cases progress to end-stage renal disease, and clinical heterogeneity in cases carrying the C3 p.I1157T mutation has been documented. In vitro studies suggest that impaired inactivation of C3b carrying the p.I1157T mutation by complement regulators may contribute to aHUS pathogenesis, but in vivo evidence remains scarce.

Objectives: To evaluate the phenotype of mice carrying the C3 p.I1157T mutation.

Methods: We generated knock-in mice homozygous for the C3 p.I1157T mutation (C3^T/T).

Results: The mice developed normally, displayed phenotypes largely indistinguishable from wild-type mice, and did not develop aHUS even under lipopolysaccharide-induced stress. Moreover, C3^T/T mice with homozygous deficiencies in Adamts13 also remained asymptomatic, without evidence of C3 overactivation. Thus, the C3 p.I1157T mutation did not promote TMA under the tested conditions in mice.

Conclusions: The phenotypic differences between humans and mice may reflect species-specific features of the complement system or indicate that additional factors are required for aHUS development. C3^T/T mice may provide a useful model for studying the potential pathophysiological roles of the C3 p.I1157T mutation.

Background: The increasing prevalence of cardiovascular diseases has resulted in a higher incidence of iatrogenic femoral artery pseudoaneurysms, which are vascular complications that occur following diagnostic or therapeutic vascular interventions. Ultrasound-guided thrombin injection (UGTI) is widely used to treat pseudoaneurysms, but challenges persist regarding complex pseudoaneurysm morphologies.

Objectives: Evaluate the performance of the UGTI under complex morphological conditions.

Methods: Six pseudoaneurysm models were developed based on clinical data and analyzed experimentally and numerically. A bidirectional pulsatile flow generator is used for plasma flow in the experimental setup, varying thrombin concentrations to pseudoaneurysm morphologies for a particular injection time. Computational fluid dynamics (CFD) simulations were also conducted to assess technical and treatment success and thromboembolism risk.

Results: A significant correlation between the morphological factors and treatment outcomes is observed in the experimental findings, where neck width was identified as the most critical parameter influencing thromboembolism and coagulation efficacy. In vitro models with neck widths ≥10 mm and lengths ≤5 mm exhibited low success rates and increased thromboembolism volumes. Variations in thrombin concentrations of 100, 500, and 1000 IU for complex shapes demonstrated higher success rates for 500 IU. A thromboembolism volume threshold of 20 mL was proposed as a cutoff value for the risk indicator. CFD simulations utilizing a thrombin-induced thrombosis model validated the experimental findings and provided insights into thrombin distribution and coagulation dynamics.

Conclusions: These results enhance the understanding of the treatment challenges in pseudoaneurysms with complex morphologies and provide practical guidelines for enhancing treatment efficacy while minimizing complications.

Background: Pulmonary embolism (PE) carries substantial mortality, but recent mortality trends and underlying causes of death among young adults during the last two decades remain insufficiently studied.

Aims: To investigate time trends in all-cause mortality within 30 days, 31-365 days, and 1-3 years among PE-patients aged 18-49 years. Secondary aims included examining mortality trends in subgroups and cause-specific mortality.

Methods: Nationwide Swedish register study of patients aged 18-49 years with first-time PE, 2006-2023. Mortality rates and temporal trends with age- and sex-adjusted rate ratios (aRRs) per 3-year interval were calculated using Poisson regression, overall and stratified by cancer, sex, age group, and pregnancy- and postpartum-related PE.

Results: Among 18,173 patients, 30-day mortality declined from 416.6 per 1,000 person-years in 2006-2008 to 262.4 in 2021-2023 (aRR, 0.89; 95% CI, 0.84-0.94) but plateaued from 2015-2017. Mortality at 31-365 days (58.6 to 44.7 per 1,000 person-years) and 1-3 years (14.7 to 14.2) remained stable over time. Among 1-year survivors, mortality declined among cancer patients (aRR, 0.84; 95% CI, 0.76-0.92). Venous thromboembolism (VTE) was the leading cause of 30-day mortality among cancer-free patients. After 30 days, cancer was the leading cause of death, including among individuals without cancer at baseline.

Conclusions: 30-day mortality after first-time PE declined early in the study period, but plateaued from 2015-2017 onward. Mortality beyond 30 days remained stable and was only marginally attributable to VTE as underlying cause, underscoring the importance of comorbidity management in post-acute PE care.

Background: Pregnant hemophilia carriers receive prophylactic Factor (F) VIII or FIX concentrate based on third-trimester FVIII/FIX activity to reduce the risk of severe postpartum hemorrhage (PPH, ≥1000 mL). Due to persistently high severe PPH rates, Dutch guidelines were revised in 2018. Consensus was reached to increase the third-trimester threshold for prophylaxis from <50 IU/dL to <80 IU/dL, and peak target levels during childbirth from ≥100 IU/dL to ≥150 IU/dL.

Methods: Pregnant hemophilia carriers were prospectively enrolled (2018-2024) in Dutch hemophilia treatment centers to assess the severe PPH incidence after implementation of the revised guideline. FVIII/FIX activity, hematologic and obstetric outcomes were recorded and compared to a historical cohort (2012-2017). Statistics included descriptives and logistic regression to correct for confounders.

Results: Severe PPH occurred in 12.4% of 170 deliveries. No thrombosis was recorded. Prophylaxis in the subgroup with third trimester levels <80 IU/dL led to similar PPH rates to those with spontaneous rises >80 IU/dL. Compared to the historic cohort with the third-trimester cut-off <50 IU/dL, the severe PPH incidence did not decrease (n=170 vs n=197, OR 1.16, 95% CI 0.46-2.93), neither in the third-trimester 50-80 IU/dL subgroup (n=28/170 vs n=21/197, OR 1.0, 95%CI 0.20-2.90).

Conclusion: Increasing the third-trimester cut-off to <80 IU/dL and aiming for ≥150 IU/dL at delivery did not decrease the risk for severe PPH in hemophilia carriers. More research is needed on optimal clotting factor levels during delivery to prevent severe PPH.

Background: Circulating levels and functionality of coagulation and fibrinolysis-related proteins are critical in bleeding and thrombosis. Traditional assays lack multiplexing and adequate standardization, and require substantial plasma volumes. Quantitative protein mass spectrometry (QPMS) enables multiplexed protein quantitation, addressing clinical and research gaps.

Objective: Develop and validate a QPMS test for multiplexed quantitation of five coagulation proteins.

Methods: A QPMS test was developed to measure plasma fibrinogen (FBG), von Willebrand factor (VWF), factor VIII (FVIII), FIX, and FXI. Three tryptic peptides were chosen as representatives for each protein. Stable isotope-labeled internal standards were synthesized for precise quantitation. Analytical validation assessed precision, linearity, specificity, stability, carryover, reference intervals, method comparison, and matrix effects.

Results: Representative peptides for protein quantitation and identity confirmation were selected. Candidate peptides for FBG, VWF, FIX and FXI produced sufficient signals in citrated and EDTA plasma, whereas FVIII candidate peptides did not. Validation (excluding FVIII) using citrated healthy subject and patient plasmas demonstrated median within-laboratory variations of 3.4-6.7% and a linear relationship (r=0.990-0.998). Signals remained stable after seven freeze/thaw cycles. A high level of agreement was shown with traditional assays (FBG: r=0.991, VWF: r=0.970, FIX: r=0.926, FXI: r=0.871). Robust relative quantitation of target proteins across different anticoagulant matrices was observed.

Conclusion: We developed and validated a QPMS test for multiplexed quantitation of FBG, VWF, FIX, and FXI. Enrichment is required for low-abundant FVIII. This study indicates analytical feasibility for the use of QPMS in diagnostics and justifies development of one QPMS test encompassing all coagulation- and fibrinolysis-related proteins.

Immunofluorescence-based platelet phenotyping using peripheral blood smears has recently emerged as a promising method for characterizing a subgroup of inherited platelet disorders (IPD). A single-center study demonstrated its potential for accurate diagnosis of 9 disorders with characteristic platelet structural changes. The aim of this study was to evaluate the reproducibility of this approach through an interlaboratory validation study. Native, air-dried blood smears from healthy controls and patients with confirmed IPD were shipped to 7 participating laboratories, blinded for the sample origin. Samples were fixed and stained using a shared panel of 13 commercially available primary antibodies and 2 fluorescence-labelled secondary antibodies. Laboratories formulated diagnostic predictions based solely on immunofluorescence findings. The pre-workshop method establishment involved other samples and feedback with the coordinating laboratory to address technical issues before blinded sample validation. All 7 laboratories (Brisbane, Greifswald, Murcia, Paris, Pavia, Perugia, and Tübingen) correctly diagnosed MYH9-related disease, Bernard-Soulier syndrome, Glanzmann thrombasthenia, and GFI1B-related thrombocytopenia. Six of 7 laboratories accurately identified TUBB1-related disorder and quantitative δ-storage pool disorder, while 5 of 7 correctly diagnosed GATA1-related thrombocytopenia. Immunofluorescence-based platelet phenotyping on peripheral blood smears demonstrated high sensitivity for diagnosing MYH9-related disease, Bernard-Soulier syndrome, Glanzmann thrombasthenia, and GFI1B-related thrombocytopenia, and reasonable sensitivity for TUBB1-related disorder, quantitative δ-storage pool disorder, and GATA1-related thrombocytopenia. Immunofluorescence analysis of blood smears may be of help in the diagnostic work-up of IPD.

Background: The anticoagulant management and outcomes in patients with cancer and distal lower extremity deep vein thrombosis (dDVT) or subsegmental pulmonary embolism (SSPE) remain unclear.

Objectives: The objective of this study was to assess the anticoagulation management strategies for dDVT and/or SSPE in patients with cancer and their associated outcomes.

Methods: We conducted a single-center retrospective cohort study in patients ≥18 years old with active cancer and dDVT and/or SSPE. Patients were followed for 12 months or until death. The primary efficacy outcome was recurrent venous thromboembolism (VTE) at 6 months, and the primary safety outcome was major bleeding. We calculated the cumulative incidence of outcomes with 95% CI, considering death as a competing risk.

Results: We identified 149 patients with isolated dDVT and 119 with SSPE ± dDVT. Anticoagulation was initiated in 85% of patients, most often with therapeutic doses. The 6-month cumulative incidences of recurrent VTE in the dDVT and SSPE cohorts were 17.9% (95% CI, 12.1-24.6) and 7.1% (95% CI, 3.3-12.9), respectively. The 6-month cumulative incidences of major bleeding were 7.9% (95% CI, 4.0-13.5) and 5.5% (95% CI, 2.2-10.9), respectively. Exploratory analysis stratified by the use of anticoagulation showed that patients not initiated on anticoagulation had a numerically higher incidence of recurrent VTE in the dDVT group.

Conclusion: Patients with cancer-associated dDVT and/or SSPE had a substantial risk of recurrent VTE, especially in those not on anticoagulation.

Introduction: Obesity is a global health concern associated with chronic low-grade inflammation that supports high cardiometabolic risk. Proinflammatory and prothrombotic states contribute to the development of cardiovascular diseases, a leading cause of mortality in obesity. Platelets are chief effectors of hemostasis and pathological thrombosis that have been highlighted for their key roles in inflammation and immunity. Platelets secrete inflammatory mediators and interact with leukocytes regulating crucial responses. However, the mechanisms and functional responses of platelet-leukocyte aggregates in obesity and their link to chronic low-grade inflammation remain elusive.

Objective: We investigate how platelet activation and platelet-leukocyte interaction contribute to inflammation in obesity.

Methods: We evaluated 87 obese patients (BMI >30) in an observational cross-sectional study and investigated mechanisms of thromboinflammatory amplification using co-culture models.

Results: We demonstrated increased platelet activation and platelet-monocyte aggregate formation during obesity, which was associated with CD16 and TF expression on monocytes. Platelet and monocyte activation were associated with metabolic syndrome and high cardiovascular risk markers in obesity. Functional experiments with isolated cells highlighted platelet orchestration of monocyte functions leading to TF expression and pro-inflammatory mediator secretion. Platelet-monocyte interaction ex vivo reciprocally activated monocytes and platelets, inducing mediator secretion from both cells. Increased TF, CD16 and mediator secretion by monocytes and platelets occurred partially through CD62P-, CD40L- and integrin αIIb/β3-dependent signaling. Finaly, conditioned medium from platelet-monocyte co-cultures promoted endothelial cell activation through IL-1 receptor.

Conclusion: Our data reveals mechanisms involving a reciprocal platelet-monocyte activation amplification loop that was associated with cardiometabolic risk and supports thromboinflammation in obesity.