Biotinylation of human platelets is compatible with pathogen inactivation treatment and cold storage for clinical studies.

Background: Production of platelet concentrates (PCs) involves several steps that significantly affect platelet behavior. To gain a deeper understanding of how storage conditions impact donor platelet recirculation and functionality post-transfusion, ex vivo platelet labeling is a feasible approach. However, before pursuing clinical investigations of platelet recirculation and function in humans, we aimed to determine the effects of pathogen inactivation technology (PIT) and storage conditions (4°C vs.

Direct oral anticoagulants in cirrhosis: Rationale and current evidence.

Cirrhosis is a major health concern worldwide with a complex pathophysiology affecting various biological systems, including all aspects of haemostasis. Bleeding risk is mainly driven by portal hypertension, but in end-stage liver disease it is further increased by alterations in haemostatic components, including platelet function, coagulation, and fibrinolysis. Concurrently, patients with cirrhosis are prone to venous thromboembolic events (VTE) because of the altered haemostatic balance, in particular an increase in thrombin generation.

Global coagulation assays detect an early prothrombotic state in children with acute lymphoblastic leukemia.

Background: Pediatric patients with acute lymphoblastic leukemia (ALL) are at highest risk of venous thromboembolism during the induction therapy (IT). These events are not predictable by conventional coagulation assays.

Objectives: To investigate the utility of global coagulation assays (GCAs) for assessing the hemostatic state in children with ALL during IT.

Inhibition of mitochondrial calcium transporters alters adp-induced platelet responses.

Introduction: ADP-stimulated elevation of cytosolic Ca is an important effector mechanism for platelet activation. The rapidly elevating cytosolic Ca is also transported to mitochondrial matrix via Mitochondrial Ca Uniporter (MCU) and extruded via Na/Ca/Li Exchanger (NCLX). However, the exact contribution of MCU and NCLX in ADP-mediated platelet responses remains incompletely understood.

Two novel platelet biotinylation methods and their impact on stored platelet concentrates in a blood bank environment.

Background: Storage of platelet concentrates (PCs) has an impact on platelet quality and possibly affects their functions after transfusion. The influence of processing and storage conditions of PCs on their in vivo function upon transfusion is unknown. One option for investigating this question is to implement an ex vivo labeling of human platelets, to analyze them after transfusion into heathy volunteers and/or patients.

Mechanisms Underlying Dichotomous Procoagulant COAT Platelet Generation-A Conceptual Review Summarizing Current Knowledge.

Procoagulant platelets are a subtype of activated platelets that sustains thrombin generation in order to consolidate the clot and stop bleeding. This aspect of platelet activation is gaining more and more recognition and interest. In fact, next to aggregating platelets, procoagulant platelets are key regulators of thrombus formation.

Thrombocytopathies: Not Just Aggregation Defects-The Clinical Relevance of Procoagulant Platelets.

Platelets are active key players in haemostasis. Qualitative platelet dysfunctions result in thrombocytopathies variously characterized by defects of their adhesive and procoagulant activation endpoints. In this review, we summarize the traditional platelet defects in adhesion, secretion, and aggregation.

Heparin-Induced Thrombocytopenia: A Review of New Concepts in Pathogenesis, Diagnosis, and Management.

Knowledge on heparin-induced thrombocytopenia keeps increasing. Recent progress on diagnosis and management as well as several discoveries concerning its pathogenesis have been made. However, many aspects of heparin-induced thrombocytopenia remain partly unknown, and exact application of these new insights still need to be addressed.

Sodium-Calcium Exchanger Reverse Mode Sustains Dichotomous Ion Fluxes Required for Procoagulant COAT Platelet Formation.

Procoagulant collagen-and-thrombin (COAT)-activated platelets represent a subpopulation of activated platelets, which retain a coat of prohemostatic proteins and express phosphatidylserine on their surface. Dichotomous intracellular signaling generating procoagulant platelet activity instead of traditional aggregating endpoints is still not fully elucidated. It has been demonstrated that secondary messengers such as calcium and sodium play a critical role in platelet activation.

How to Capture the Bleeding Phenotype in FXI-Deficient Patients.

Factor XI (FXI) is a serine protease involved in the propagation phase of coagulation and in providing clot stability. Several mutations in the gene lead to FXI deficiency, a rare mild bleeding disorder. Current laboratory methods are unable to assess bleeding risk in FXI-deficient patients, because the degree of bleeding tendency does not correlate with plasma FXI activity as measured by routine coagulometric aPTT-based assays.

Tissue Factor-Independent Coagulation Correlates with Clinical Phenotype in Factor XI Deficiency and Replacement Therapy.

Background:  In factor XI (FXI) deficiency, bleeding cannot be predicted by routine analyses. Since FXI is involved in tissue factor (TF)-independent propagation loop of coagulation, we hypothesized that investigating the spatiotemporal separated phases of coagulation (TF-dependent and -independent) could improve diagnostics.

Objectives:  This article investigates the correlation of parameters describing TF-dependent and -independent coagulation with the clinical phenotype of FXI deficiency and their ability to assess hemostasis after FXI replacement.

Biomarkers of liver dysfunction correlate with a prothrombotic and not with a prohaemorrhagic profile in patients with cirrhosis.

Background & Aims: Different liver dysfunction biomarkers are used to assess the bleeding risk of patients with cirrhosis, either as such or included in bleeding risk assessment scores. Since the current model of coagulation in patients with cirrhosis describes a procoagulant tendency with increasing severity according to Child-Pugh stage, we decided to investigate the relation between liver dysfunction biomarkers and thrombin generation. Our aim was to verify their adequacy for bleeding risk assessment.

Flow Cytometric Monitoring of Dynamic Cytosolic Calcium, Sodium, and Potassium Fluxes Following Platelet Activation.

The interaction of platelet agonists with their respective membrane receptors triggers intracellular signaling, among which cytosolic ion fluxes play an important role in activation processes. While the key contribution of intercellular free calcium is accepted, sodium and potassium roles in platelet activation have been less investigated in recent studies. Here, we implemented a novel flow-cytometric method to monitor over time cytosolic free calcium, sodium, and potassium ion fluxes upon platelet activation and we demonstrate the feasibility of real-time visualization of ion kinetics, in particular with a focus on sodium and potassium.

Thrombin generation in a woman with heterozygous factor V Leiden and combined oral contraceptives: A case report.

Combined oral contraceptives and factor V Leiden mutation are multiplicative risk factors for venous thromboembolism. However, it remains unknown whether this multiplicative effect is reflected in thrombin generation assays. We report here the evolution of the thrombin generation profile while taking combined oral contraceptives and after their discontinuation in a woman with heterozygous factor V Leiden mutation.

Hemostatic Alterations in Patients With Cirrhosis: From Primary Hemostasis to Fibrinolysis.

In the setting of liver cirrhosis (LC), profound hemostatic changes occur, which affect primary hemostasis, coagulation, and fibrinolysis. They involve prohemorrhagic and prothrombotic alterations at each of these steps. Patients with cirrhosis exhibit multifactorial thrombocytopenia and in vitro thrombocytopathy, counterbalanced by increased von Willebrand factor.

Hyper-coagulability in obese patients accurately identified by combinations of global coagulation assay parameters.

Background: Routine laboratory methods are insensitive to hyper-coagulation, which may be detected by global hemostasis tests. Calibrated Automated Thrombogram (CAT) is a gold standard method to measure thrombin generation and coagulation potential. Thrombodynamics (TD) is a new global assay that monitors the spatio-temporal propagation of blood coagulation, separating initiation from amplification/propagation phases of coagulation and visualizing fibrin clot formation.

The effect of bariatric surgery on the direct oral anticoagulant rivaroxaban: the extension study.

Background: Thromboembolic disease is a potentially serious complication in bariatric surgery patients. Direct oral anticoagulants (DOAC) have been investigated in orthopedic surgery patients. DOAC data after bariatric surgery are still limited to the early postsurgical period.

Generation of procoagulant collagen- and thrombin-activated platelets in platelet concentrates derived from buffy coat: the role of processing, pathogen inactivation, and storage.

Background: Collagen- and thrombin-activated (COAT) platelets (PLTs), generated by dual-agonist stimulation with collagen and thrombin (THR), enhance THR generation at the site of vessel wall injury. There is evidence that higher amounts of procoagulant COAT PLTs are associated with stroke, while a decreased ability to generate them is associated with bleeding diathesis. Our aim was to study PLT functions, particularly the ability to generate COAT PLTs, in PLT concentrates (PCs) from buffy coat.

Circadian variation of ticagrelor-induced platelet inhibition in healthy adulty.

Aims: The circadian variation of platelet aggregation is well demonstrated. However, whether this has an impact on antiplatelet inhibition therapy is poorly documented. We aimed to observe whether ticagrelor-induced platelet inhibition follows a circadian rhythm.