Interpreting high levels of unfolded Von Willebrand Factor in patients with the antiphospholipid syndrome.

Introduction: Unfolded Von Willebrand Factor (VWF) is increased in thrombotic pathologies such as myocardial infarction. Unfolded VWF mediates the binding of platelets without the need for collagen. β-glycoprotein I (β-GPI) is a natural inhibitor of the platelet-VWF interaction.

Thrombomodulin is a stronger indicator of combined oral contraceptives-induced activated protein C pathway resistance in the thrombin generation test than activated protein C.

Background: The mechanism by which combined oral contraceptives (COCs) lead to hypercoagulation is not fully understood, although activated protein C (APC) pathway resistance has been implicated. APC and thrombomodulin (TM) tend to be considered as interchangeable reagents, even though their biological action in coagulation is different. However, it remains unclear which reagent is better suited for the detection of APC pathway resistance.

Low thrombin inactivation capacity is associated with an increased risk of recurrent ischemic events after ischemic stroke at a young age.

Background: Patients with ischemic stroke at a young age (18-50 years) have an increased long-term risk of recurrent ischemic events. Hypercoagulability may contribute to this high risk.

Objectives: To investigate the associations between in vivo and ex vivo hemostatic parameters and recurrent ischemic events after an ischemic stroke or transient ischemic attack (TIA) at a young age.

Impaired whole blood thrombin generation is associated with procedure-related bleeding in acutely decompensated cirrhosis.

Background & Aims: The clinical utility of thrombomodulin-modified thrombin generation (TM-TG) in cirrhosis is uncertain. We conducted a prospective study to evaluate the prognostic value of TM-TG in cirrhosis.

Methods: Patients were recruited during outpatient clinics (compensated and stable decompensated) or if admitted to our inpatient service (acutely decompensated, AD).

Functionally distinct anticoagulant mechanisms of endothelial cells.

Antithrombin and tissue factor pathway inhibitor (TFPI) provide different anticoagulant mechanisms. Having established a potent anticoagulant role of cultured human umbilical vein endothelial cells in vessel-on-a-chip microfluidic models, we now investigated how these cells modulated thrombin generation under stasis through antithrombin and TFPI pathways. We observed that endothelial monolayers in 96 well-plates strongly delayed and suppressed the thrombin generation process induced by tissue factor, regardless of the presence of whole blood, platelet-rich plasma or platelet-free plasma.

An update on laboratory detection and interpretation of antiphospholipid antibodies for diagnosis of antiphospholipid syndrome: guidance from the ISTH-SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies.

Antiphospholipid syndrome (APS) diagnosis is dependent on the accurate detection and interpretation of antiphospholipid antibodies (aPL). Lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-beta2 glycoprotein I antibodies (aβ2GPI) remain the cornerstone of the laboratory part of APS diagnosis. In the 2023 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) APS classification criteria, the type of laboratory parameters remain essentially unchanged compared with the updated Sapporo classification criteria, and aCL and aβ2GPI measurement are still restricted to enzyme-linked immunosorbent assays (ELISAs) with moderate and high titer aPL thresholds defined as 40 and 80 Units, respectively, and a cutoff calculated by the 99th percentile has been abandoned.

Interference of lupus anticoagulant causing antiprothrombin and anti-beta-2-glycoprotein I antibodies on international normalized ratio measurements: comparative analysis of international normalized ratio methods.

Background: Life-long vitamin K antagonist (VKA) therapy is recommended as a standard of care in antiphospholipid syndrome (APS) patients with thrombosis. Concerns have been raised about the validity of international normalized ratio (INR) measurements in lupus anticoagulant (LA)-positive APS patients because LA may interfere with phospholipid-dependent coagulation tests and could elevate INR measurements.

Objectives: Here, we aimed to determine the interference of antigen-specific monoclonal and isolated patient antibodies with LA activity on INR measurements.

Comprehensive functional characterization of a novel ANO6 variant in a new patient with Scott syndrome.

Background: Scott syndrome is a mild platelet-type bleeding disorder, first described in 1979, with only 3 unrelated families identified through defective phosphatidylserine (PS) exposure and confirmed by sequencing. The syndrome is distinguished by impaired surface exposure of procoagulant PS on platelets after stimulation. To date, platelet function and thrombin generation in this condition have not been extensively characterized.

Lipid nanoparticles and siRNA targeting plasminogen provide lasting inhibition of fibrinolysis in mouse and dog models of hemophilia A.

Antifibrinolytic drugs are used extensively for on-demand treatment of severe acute bleeding. Controlling fibrinolysis may also be an effective strategy to prevent or lessen chronic recurring bleeding in bleeding disorders such as hemophilia A (HA), but current antifibrinolytics have unfavorable pharmacokinetic profiles. Here, we developed a long-lasting antifibrinolytic using small interfering RNA (siRNA) targeting plasminogen packaged in clinically used lipid nanoparticles (LNPs) and tested it to determine whether reducing plasmin activity in animal models of HA could decrease bleeding frequency and severity.

Viewpoint: The value of non-criteria antiphospholipid antibodies.

In 2006, at a meeting in Sydney, Australia, consensus was reached by an international group of specialists to establish a number of serological criteria that identify patients with a history of thrombosis or pregnancy complications as having antiphospholipid syndrome (APS). These criteria were originally formulated for research purposes and to compare clinical trials in different centres. However, these same criteria are now generally used and accepted for the diagnosis and treatment of patients.

Altered whole blood thrombin generation and hyperresponsive platelets in patients with pancreatic cancer.

Background: Thromboembolic disease is a major complication in patients with pancreatic ductal adenocarcinoma (PDAC). Patients with PDAC often have altered blood cell counts, which are associated with venous thromboembolism (VTE) development. The high thrombotic risk in patients with PDAC may be partially caused by procoagulant blood cells.

High alpha-2-macroglobulin levels are a risk factor for cardiovascular disease events: A Moli-sani cohort study.

Background: α-macroglobulin (αM) is a versatile endopeptidase inhibitor that plays a role in cell growth, inflammation and coagulation. αM is an inhibitor of key coagulation enzyme thrombin. Hypercoagulability due to an excess of thrombin production can cause thrombotic events.

Cellular Components Contributing to the Development of Venous Thrombosis in Patients with Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive type of cancer and has a poor prognosis. Patients with PDAC are at high risk of developing thromboembolic events, which is a leading cause of morbidity and mortality following cancer progression. Plasma-derived coagulation is the most studied process in cancer-associated thrombosis.

Plasminogen deficiency suppresses pancreatic ductal adenocarcinoma disease progression.

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal metastatic disease associated with robust activation of the coagulation and fibrinolytic systems. However, the potential contribution of the primary fibrinolytic protease plasminogen to PDAC disease progression has remained largely undefined. Mice bearing C57Bl/6-derived KPC (KRas , TRP53 ) tumors displayed evidence of plasmin activity in the form of high plasmin-antiplasmin complexes and high plasmin generation potential relative to mice without tumors.

Whole blood thrombin generation shows a significant hypocoagulable state in patients with decompensated cirrhosis.

Background: Patients with cirrhosis have a normal to increased thrombin generation (TG) capacity in platelet-poor plasma (PPP). By reflecting the contribution of all circulating blood cells, whole blood (WB) TG may allow a more physiological assessment of coagulation.

Objectives: We compared WB-TG vs PPP-TG in patients with cirrhosis.

Crucial roles of red blood cells and platelets in whole blood thrombin generation.

Red blood cells (RBCs) and platelets contribute to the coagulation capacity in bleeding and thrombotic disorders. The thrombin generation (TG) process is considered to reflect the interactions between plasma coagulation and the various blood cells. Using a new high-throughput method capturing the complete TG curve, we were able to compare TG in whole blood and autologous platelet-rich and platelet-poor plasma to redefine the blood cell contributions to the clotting process.

Periprocedural continuation versus interruption of oral anticoagulant drugs during transcatheter aortic valve implantation: rationale and design of the POPular PAUSE TAVI trial.

About one-third of patients undergoing transcatheter aortic valve implantation (TAVI) use oral anticoagulants (OAC), mainly due to atrial fibrillation. General guidelines advise interrupting OAC in patients with a high risk of bleeding undergoing interventions. However, preliminary observational data suggest that the continuation of OAC during TAVI is safe and may reduce the risk of periprocedural thromboembolic events.