Review of laboratory methods used for analysis of von Willebrand factor and for diagnosis of related diseases.

Introduction: Von Willebrand factor (VWF) is a large multimeric protein present in the blood. Its most important and best characterized function is to control bleeding in primary hemostasis, which is triggered by different biophysical mechanisms and protein-receptor interactions involving different domains of VWF. Many different diseases related to VWF, most importantly von Willebrand disease comprising different types and sub-types, require diagnosis, laboratory analysis of concentration, and function of VWF.

Von Willebrand factor is a multifaceted player in hemostasis requiring a diverse array of analytical and diagnostic approaches.

Introduction: Von Willebrand factor (VWF) plays a crucial role in hemostasis: its interactions with endothelial matrices, platelets, and factor VIII make it a key player in both primary hemostasis and coagulation. Pathology associated with VWF spans mild to severe bleeding manifestations in the case of inherited von Willebrand disease (VWD), the most common congenital bleeding disorder, or acquired von Willebrand syndrome (AVWS). Conversely, VWF can be associated with thrombotic manifestations in situations related to inflammation, infection, or inherited or acquired ADAMTS13 defects.

Pharmacokinetics, pharmacodynamics, and safety of fesomersen, a novel antisense inhibitor of factor XI, in healthy Chinese, Japanese, and Caucasian volunteers.

The inhibition of coagulation factor XI (FXI) presents an attractive approach for anticoagulation as it is not expected to increase the risk of clinically relevant bleeding and is anticipated to be at least as effective as currently available anticoagulants. Fesomersen is a conjugated antisense oligonucleotide that selectively inhibits the expression of FXI. The article describes three clinical studies that investigated the safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles of fesomersen after subcutaneous (s.

Longitudinal observations of TFPI levels in paediatric Haemophilia A patients.

Introduction: Inhibition of tissue factor pathway inhibitor (TFPI) is a potential new mode of action to achieve haemostasis in haemophilia A and B patients.

Aim: Knowledge about potential developmental changes of TFPI levels during childhood are a prerequisite to translate adult doses of TFPI inhibitors to doses in paediatric patients.

Methods: In this study we present longitudinal data for total TFPI concentrations (TFPI-T) and TFPI activity (TFPI-A) from 48 paediatric Haemophilia A patients in the age range from 3 to 18 years (2-12 observations per patient).

Predictive value for increased activated factor XI activity in acute venous thromboembolism.

Background: Venous thromboembolism (VTE) is associated with excessive coagulation activity, which in part can be attributed to activation of contact system. However, the knowledge regarding the impact of contact activation in acute VTE is limited.

Objective: To unravel the involvement of contact activation in acute VTE.

The effect of rivaroxaban on biomarkers in blood and plasma: a review of preclinical and clinical evidence.

Rivaroxaban is a direct, oral factor Xa inhibitor that is used for the prevention and treatment of various thromboembolic disorders. Several preclinical and clinical studies have utilized specific molecules as biomarkers to investigate the potential role of rivaroxaban beyond its anticoagulant activity and across a range of biological processes. The aim of this review is to summarize the existing evidence regarding the use of blood-based biomarkers to characterize the effects of rivaroxaban on coagulation and other pathways, including platelet activation, inflammation and endothelial effects.

Subtype-specific plasma signatures of platelet-related protein releasate in acute pulmonary embolism.

Introduction: There is evidence that plasma protein profiles differ in the two subtypes of pulmonary embolism (PE), isolated PE (iPE) and deep vein thrombosis (DVT)-associated PE (DVT-PE), in the acute phase. The aim of this study was to determine specific plasma signatures for proteins related to platelets in acute iPE and DVT-PE compared to isolated DVT (iDVT).

Methods: Within the Genotyping and Molecular Phenotyping of Venous ThromboEmbolism (GMP-VTE) Project, a multicenter prospective cohort study of 693 confirmed VTE cases, a highly sensitive targeted proteomics approach based on dual-antibody proximity extension assay was applied.

Association of FXI activity with thrombo-inflammation, extracellular matrix, lipid metabolism and apoptosis in venous thrombosis.

Animal experiments and early phase human trials suggest that inhibition of factor XIa (FXIa) safely prevents venous thromboembolism (VTE), and specific murine models of sepsis have shown potential efficacy in alleviating cytokine storm. These latter findings support the role of FXI beyond coagulation. Here, we combine targeted proteomics, machine learning and bioinformatics, to discover associations between FXI activity (FXI:C) and the plasma protein profile of patients with VTE.

First randomized evaluation of safety, pharmacodynamics, and pharmacokinetics of BAY 1831865, an antibody targeting coagulation factor XI and factor XIa, in healthy men.

Background: Bleeding is a clinically significant issue with all current anticoagulants. Safer antithrombotic strategies are required.

Objectives: To investigate the safety, pharmacodynamics, and pharmacokinetics of BAY 1831865, a humanized, factor XI (FXI)-directed monoclonal antibody, after single intravenous (i.

Pharmacokinetics, pharmacodynamics and safety of BAY 2433334, a novel activated factor XI inhibitor, in healthy volunteers: A randomized phase 1 multiple-dose study.

Aim: To evaluate BAY 2433334, an oral activated factor XI (FXIa) inhibitor, in volunteers.

Methods: Phase 1 study of healthy men at a German centre. Part A: randomized, single-blind, multiple dose-escalation study of BAY 2433334 (25/50/100 mg once daily [OD]) vs.

Clinical use of thrombin generation assays.

Determining patient's coagulation profile, i.e. detecting a bleeding tendency or the opposite, a thrombotic risk, is crucial for clinicians in many situations.

Thrombin generation assays are versatile tools in blood coagulation analysis: A review of technical features, and applications from research to laboratory routine.

Thrombin is the pivotal enzyme in the biochemistry of secondary hemostasis crucial to maintaining homeostasis of hemostasis. In contrast to routine coagulation tests (PT or aPTT) or procoagulant or anticoagulant factor assays (e.g.

First evaluation of the safety, pharmacokinetics, and pharmacodynamics of BAY 2433334, a small molecule targeting coagulation factor XIa.

Background: Coagulation factor XI (FXI) contributes to the development of thrombosis but appears to play a minor role in hemostasis and is, therefore, an attractive anticoagulant drug target.

Objectives: To evaluate the safety, pharmacokinetic, and pharmacodynamic properties of BAY 2433334, an orally administered small molecule targeting activated FXI (FXIa), in healthy men.

Patients/methods: This phase 1 study was conducted in two parts.

BAY 1213790, a fully human IgG1 antibody targeting coagulation factor XIa: First evaluation of safety, pharmacodynamics, and pharmacokinetics.

Background: Coagulation factor XI (FXI) contributes to the development of thrombosis but appears to play only a minor role in hemostasis and is therefore an attractive anticoagulant drug target.

Objectives: To evaluate the safety, pharmacodynamic, and pharmacokinetic properties of BAY 1213790, a fully human immunoglobulin (Ig) G1 antibody targeting activated coagulation FXI (FXIa), in healthy men.

Methods: In this phase 1, single-blind, parallel-group, placebo-controlled, dose-escalation study, 83 healthy Caucasian men were randomized 4:1 to receive a single 60-minute intravenous infusion of BAY 1213790 (0.

Safety and efficacy of the human neutrophil elastase inhibitor BAY 85-8501 for the treatment of non-cystic fibrosis bronchiectasis: A randomized controlled trial.

Background: There are only limited treatment options for patients with non-cystic fibrosis bronchiectasis (non-CF BE). Human neutrophil elastase (HNE) is a mediator of tissue destruction in non-CF BE. BAY 85-8501, a selective and reversible HNE inhibitor, could represent a new treatment option for this disease.

Rivaroxaban and other novel oral anticoagulants: pharmacokinetics in healthy subjects, specific patient populations and relevance of coagulation monitoring.

Unlike traditional anticoagulants, the more recently developed agents rivaroxaban, dabigatran and apixaban target specific factors in the coagulation cascade to attenuate thrombosis. Rivaroxaban and apixaban directly inhibit Factor Xa, whereas dabigatran directly inhibits thrombin. All three drugs exhibit predictable pharmacokinetic and pharmacodynamic characteristics that allow for fixed oral doses in a variety of settings.

Investigation of Pharmacodynamic and Pharmacokinetic Interactions Between Rivaroxaban and Enoxaparin in Healthy Male Subjects.

Rivaroxaban, an oral, direct factor Xa inhibitor, is currently used in clinical practice for the prevention and treatment of thromboembolic disorders. This single-center, three-way crossover study was designed to investigate the pharmacodynamic effects of rivaroxaban (10 mg) and enoxaparin (40 mg) alone and in combination as well as the influence of enoxaparin on the pharmacokinetics of rivaroxaban in healthy male subjects. When given alone, both drugs exhibited similar, rapid anti-factor Xa activity.

Accurate determination of rivaroxaban levels requires different calibrator sets but not addition of antithrombin.

Rivaroxaban is a direct factor Xa inhibitor, which can be monitored by anti-factor Xa chromogenic assays. This ex vivo study evaluated different assays for accurate determination of rivaroxaban levels. Eighty plasma samples from patients receiving rivaroxaban (Xarelto) 10 mg once daily and 20 plasma samples from healthy volunteers were investigated using one anti-factor Xa assay with the addition of exogenous antithrombin and two assays without the addition of antithrombin.

Effect of co-administration of rivaroxaban and clopidogrel on bleeding time, pharmacodynamics and pharmacokinetics: a phase I study.

Dual antiplatelet therapy with acetylsalicylic acid and a thienopyridine, such as clopidogrel, is effective for the secondary prevention of cardiovascular events in patients with acute coronary syndrome, but there is still a substantial residual risk of recurrence. Although anticoagulant therapy with a vitamin K antagonist (e.g.

A high-sensitivity, medium-density, and target amplification-free planar waveguide microarray system for gene expression analysis of formalin-fixed and paraffin-embedded tissue.

Background: Many microarray platforms and their associated assay chemistries do not work properly with RNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissue samples, a feature that severely hampers the use of microarrays in oncology applications, for which FFPE tissue is the routine specimen. Furthermore, the limited sensitivity of most microarray platforms requires time-consuming and costly amplification reactions of the target RNA, which negatively affects clinical laboratory work flow.

Methods: We developed an approach for sensitively and reliably measuring mRNA abundances in FFPE tissue samples.

Stochastic pairing of Ig heavy and light chains frequently generates B cell antigen receptors that are subject to editing in vivo.

We examined the generation and selection of the B cell antibody repertoire through crossing of mice bearing distinct Ig heavy (H) and light (L) chain rearranged variable region transgenes. Ig gene knock-in and transgenic mice whose H and L chains pair to form a non-autoreactive, functional B cell antigen receptor (BCR) have significantly reduced pre-B cells in the bone marrow as their B cell progenitors rapidly differentiate into surface IgM(+) B cells. The presence of a pre-B cell compartment in these Ig transgenic mice, however, indicates the induction of receptor editing.