Thrombosis and haemostasis最新文献

Introduction: Rapidly sorting patients with large vessel occlusion (LVO) ischemic stroke is crucial to ensure efficient transfers to stroke units. Peripheral monocyte subsets (classical-Mon1, intermediate-Mon2, non-classical-Mon3) could be interesting candidate biomarkers in this setting: their profiles in the first hours after stroke symptom onset are unknown.

Aim: To characterize monocyte subsets in patients admitted to emergency units for acute stroke suspicion Methods: BOOST ("Biomarkers-algOrithm-for-strOke-diagnoSis-and-Treatment-resistance-prediction", NCT04726839) is a prospective multicenter cohort. Adult patients with symptoms suggesting acute stroke within the last 24 hours were included. Blood was collected upon admission before brain imaging. Flow-cytometry (FCM) was performed on fresh blood with gating based on CD45/CD14/CD16/CD91 as well as on activation markers (CD62L/CD11b/CD86/HLA-DR/CCR2/ICAM-1/CX3CR1/TF).

Results: Of the 298 consecutive patients tested, mean age 64.0±18.6 years, 64 (21.5%) had LVO stroke vs 234 (78.5%) other diagnosis (non-LVO ischemic stroke, cerebral venous thrombosis, intracranial hemorrhage, transient ischemic attack and stroke mimics). The median time from symptom onset to sampling was 2.3 hours. We found a significantly lower proportion of Mon3 (geometric mean) (-47%, p=0.0093) and a higher proportion of Mon1 (+1.6%, p=0.0296), suggesting earlier Mon1 mobilization and patrolling Mon3 consumption in LVO-patients versus those without. Using linear-mixed-effect model, significant differences in ICAM-1 and HLA-DR expression on monocyte subsets were evidenced between LVO and other patients.

Conclusions: This is the first study to evidence monocyte subset differences in LVO vs non-LVO patients at the time of admission, indicating an acute systemic response in LVO. Whether Mon assessment would add value for LVO-diagnosis remains to be determined.

Once released into human blood, Shiga toxins (Stx) interact with platelets and leukocytes, stimulating them to form aggregates and to release pathogenic extracellular vesicles (EV) containing Stx. These EV are considered the trigger driving the transition from bloody diarrhea to the life-threatening hemolytic uremic syndrome (HUS) during human infections by Stx-producing Escherichia coli (STEC). In children, HUS is characterized by hemolytic anemia, thrombocytopenia and acute renal failure. The risk of any STEC-infected patient of developing HUS varies significantly depending on the Stx type produced by the bacteria, i.e. it is negligible for Shiga toxin 1 (Stx1), relevant for Shiga toxin 2 (Stx2) and considerably reduced when both toxins are present. To mimic what happens in the bloodstream of patients, human blood was challenged with Stx2a, Stx1a or both toxins and the formation of leukocyte/platelet aggregates was evaluated by direct-flow cytometric analysis. Pathogenic blood cell-derived EV were then isolated, their number and size determined by nanoparticle tracking analysis and their proteins characterized by capillary Western blotting. We found that the presence of Stx1a during Stx2a challenge significantly reduced the formation of pathogenic EV, particularly the large (>300 nm) EV population causing HUS development. Notably, the amount of Stx2a significantly decreased in Stx1a+Stx2a-triggered EV with respect to Stx2a-induced EV. Our findings suggest that in STEC-infected children the presence of Stx1 in association with Stx2 reduces the risk of developing HUS by lowering the release of Stx2-containing blood cell-derived EV which are considered the main culprits for HUS onset.

Background: Epidemiological and experimental studies suggest cocoa flavanols and multivitamin-multimineral (MVM) supplements may confer arterial vascular benefits. However, their effects on clinical venous thromboembolic events have been infrequently examined.

Objective: To evaluate whether cocoa extract (CE) or MVM supplementation reduces the risk of venous thromboembolism (VTE) among older adults.

Methods: We conducted an ancillary study analysis of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a completed randomized, double-blind, placebo-controlled, 2-by-2 factorial trial of CE and MVM supplementation for the prevention of cardiovascular disease and cancer among 21,442 older US adults. Our primary outcome was self-reported incident VTE, defined as the first reported deep vein thrombosis (DVT) or pulmonary embolism (PE) event after randomization; secondary outcomes were the individual components.

Results: Over a median follow-up of 3.5 years, 379 participants reported an incident VTE event (including 277 DVT and 165 PE). In intention-to-treat analyses, neither CE (HR: 0.88; 95% CI: 0.72, 1.08) nor MVM (HR: 0.89; 95% CI: 0.73, 1.09) significantly reduced VTE risk, with similar findings for DVT and PE. Exploratory latency and per-protocol analyses suggested potential patterns of benefit that merit further evaluation.

Conclusions: In this large trial of older adults, neither CE nor MVM supplementation significantly reduced the risk of VTE or its component parts in intention-to-treat analyses. Additional research may help clarify whether these supplements influence VTE risk in other contexts or populations.

Hemophilia B is a rare inherited bleeding disorder resulting from mutations in the coagulation factor IX (factor IX) gene. While mutations in factor IX catalytic domains directly compromise clotting activity, mutations in the signal peptide and propeptide domains contribute to disease pathogenesis through more complex and indirect mechanisms. Despite not participating directly in enzymatic catalysis, the signal peptide and propeptide domains are indispensable for proper factor IX biosynthesis, structural maturation, and post-translational modifications. Research on these regions remains limited, and the precise molecular mechanisms linking mutations in the signal peptide and propeptide domains to clinical manifestations are not yet fully elucidated. In this review, we systematically catalog pathogenic mutations identified in factor IX's signal peptide and propeptide domains, organizing them by mutation types and functional consequences. We highlight how these mutations disrupt domain integrity, compromise factor IX stability, and interfere with its physiological processing. Furthermore, we discuss additional modifiers of disease severity, such as vitamin K availability, hypersensitivity to anticoagulant therapies, and inhibitor development. By integrating genetic, biochemical, and clinical perspectives, this review highlights the crucial role of factor IX's signal peptide and propeptide domains in the pathogenesis of hemophilia B and provides a foundational mechanistic framework that may inform future therapeutic development and help elucidate the molecular basis of disease heterogeneity.

None.

Risk of venous thromboembolism (VTE) is increased in pregnancy and postpartum, and 40% of VTEs in pregnancy (Caucasians) are associated with heterozygous factor V Leiden mutation (FVL). Thrombin generation is increased in individuals with FVL and in pregnant women, and thrombin amplifies both platelet and coagulation activation. Although both contribute to VTE pathophysiology, the mechanisms of platelet activation in pregnant women, particularly with heterozygous FVL, remain poorly understood.To describe the physiological course of the platelet activation marker plasma soluble P-selectin (sP-selectin), whole blood platelet aggregation, and thromboelastography (TEG) parameters throughout pregnancy and postpartum, and assess differences between women with and without heterozygous FVL.A total of 22 pregnant women with heterozygous FVL and 22 without were enrolled. Blood samples were collected at multiple time points during and after pregnancy. Platelet activation and aggregation were evaluated using sP-selectin, multiple electrode aggregometry (MEA) with adenosine diphosphate, arachidonic acid, thrombin receptor-activating peptide-6 as agonists, and TEG.sP-selectin levels increased significantly during pregnancy, while platelet aggregation decreased in response to all agonists (P < 0.005). TEG maximum amplitude (MA) increased throughout pregnancy. No significant differences were observed between women with and without FVL.In late pregnancy, decreased platelet aggregation responses were observed alongside increased sP-selectin levels, with no differences in levels between women with and without heterozygous FVL. These findings indicate that the presence of heterozygous FVL does not significantly influence platelet function during pregnancy. The cause of the unexpected, reduced platelet aggregation remains unclear and warrants further investigation.

Platelets are among the most abundant cells in the body and play important roles in coagulation and immunity. Platelets are formed when hematopoietic stem cells proliferate and differentiate into megakaryocytes via the regulation of various cytokines. After the megakaryocytes mature in the bone marrow cavity, proplatelets are released into the blood circulation where they eventually remodel into mature platelets. Given that the production and functions of platelets involve the regulation of many factors-such as hematopoietic stem cells, the hematopoietic microenvironment, and cytokines-the causes and mechanisms of platelet-related diseases are diverse, often involving platelet production, clearance, and distribution. In this review, we examined the regulation of platelet production and summarized common disorders affecting platelet quantity, namely, thrombocytopenia and thrombocytosis. In addition, we reviewed previous clinical studies and summarized the medication strategies commonly used for the treatment of different platelet disorders in different clinical scenarios.

Coronavirus disease 2019 (COVID-19) is often associated with thrombosis. Elevated levels of soluble C-type lectin-like receptor 2 (sCLEC-2), a biomarker for platelet activation, have been reported in COVID-19. Therefore, we examined the behavior of sCLEC-2 levels and their relationship with thrombosis.The clinical course of inflammatory and thrombotic biomarkers was assessed in 271 patients with COVID-19.Inflammatory biomarkers such as C-reactive protein, procalcitonin, and presepsin levels were significantly increased in patients with COVID-19, and these behaviors differed among the clinical course or stages. The plasma D-dimer levels increased slightly and gradually. Platelet counts were within the normal range, and plasma sCLEC-2 levels were markedly increased in most patients with COVID-19. There were 17 patients with thrombosis in this study. Although there was no significant difference in various biomarkers between COVID-19 patients with and without thrombosis, the super formula of sCLEC-2xD-dimer/platelet count in patients with thrombosis was significantly higher than in those without thrombosis. Furthermore, this super formula was significantly higher in COVID-19 patients with severe or critical illness than in those with mild or moderate illness.Elevation of the super formula of sCLEC-2xD-dimer/platelet count was associated with the thrombosis in patients with COVID-19 suggesting the thrombosis in COVID-19 may be caused by the development of microthrombosis.

Protein C (PC) activation on endothelial cells is a critical antithrombotic mechanism. Hereditary PC deficiency (PCD), which is caused by mutations in the PROC gene, can predispose affected individuals to thrombophilia. Previous studies investigated activated protein C (APC) generation in PCD patients without including endothelial cells, which are essential for physiological PC activation. This study aimed to assess APC generation in PCD patients using a novel endothelial cell-based assay.Plasma samples from 21 patients with 19 heterozygous PROC mutations (median PC level 58%) and 24 healthy controls were analyzed. Endothelium-dependent APC generation was initiated by overlaying plasma on human umbilical vein endothelial cells (HUVECs) and adding tissue factor (1 pmol/L). APC levels were quantified using an oligonucleotide-based enzyme capture assay. The area under the curve (AUC) was calculated to monitor cumulative APC formation over time. A calibration curve generated from wild-type PC in PC-deficient plasma established reference ranges.Mean peak levels of APC were significantly lower in PCD patients than in healthy controls (0.75 vs. 1.83 nmol/L, p = 2 × 10^-10). The AUC APC was below the reference range in 8 of 21 (38%) patient samples, indicating disproportionately severe impairment in APC generation. The observed variability in APC generation suggests that endothelial contributions may identify functional differences undetected by standard PC activity or antigen assays.This study introduces a novel endothelial cell-based APC generation assay, demonstrating the functional consequences of PROC mutations and providing insights into the regulation of APC generation, with potential applications in thrombosis risk assessment and personalized therapy.

von Willebrand disease (VWD) type 2 arises from variants in von Willebrand factor (VWF) that disrupt its essential hemostatic functions. As per ISTH guidelines, it is classified as type 2A, 2B, 2M, and 2N based on the affected VWF roles.This population-based study aims to uncover the genotype and laboratory phenotypes in type 2 VWD, providing insights into underlying genetics and genotype-phenotype associations.Our cohort included 247 patients from 196 families. Patients were characterized through multiple VWF phenotypic assays and genetic analyses, including DNA sequencing, copy number variation evaluations, and bioinformatic assessments.A total of 86 index patients (IPs, 44%) were diagnosed with type 2A, the most prevalent subtype. Additionally, 27 IPs (14%) were diagnosed with type 2N, 24 IPs (12%) with type 2B, 17 IPs (9%) with type 2M, and 42 IPs categorized as type U VWD carried VWD-associated variants but could not be assigned to a specific subtype. VWF variants were detected in 187 out of 196 (95%) individuals. A total of 222 VWF variants were identified: 187 missense (84%), 22 null alleles (10%), 5 regulatory (2%), 6 gene conversions (3%), and 2 silent variants (1%). Many variants were recurrent in our cohort, resulting in 114 distinct variants. Of these, 45 (39%) were novel.Our data expands the spectrum of disease-associated variants in VWF, including many newly identified variants. This provides valuable insights for accurate diagnosis and personalized treatment. Additionally, the significant genetic heterogeneity among type 2 patients highlights the challenges in sub-classification.