Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic site.

Background: Salvianolic acid B (SAB) is a major component of root (Danshen), widely used in East/Southeast Asia for centuries to treat cardiovascular diseases. Danshen depside salt, 85% of which is made up of SAB, is approved in China to treat chronic angina. Although clinical observations suggest that Danshen extracts inhibited arterial and venous thrombosis, the exact mechanism has not been adequately elucidated.

Apolipoprotein A-IV polymorphisms Q360H and T347S attenuate its endogenous inhibition of thrombosis.

Platelets are small anucleate cells that play a key role in thrombosis and hemostasis. Our group previously identified apolipoprotein A-IV (apoA-IV) as an endogenous inhibitor of thrombosis by competitive blockade of the αIIbβ3 integrin on platelets. ApoA-IV inhibition of platelets was dependent on the N-terminal D5/D13 residues, and enhanced with absence of the C-terminus, suggesting it sterically hinders its N-terminal platelet binding site.

Constitutive hypercoagulability in pediatric sickle cell disease patients with hemoglobin SS genotype.

Background: Constitutive inflammation and hemostatic activation have been identified as key contributors to the pathophysiology of sickle cell disease (SCD), leading to clinical consequences such as vaso-occlusive crises and stroke. Patients with hemoglobin SS (HbSS) and hemoglobin SC (HbSC) genotypes are reported to have different symptoms, as do patients in steady-state and crisis situations. Differences among these groups remain unclear in pediatric patients.

IVIg treatment increases thrombin activation of platelets and thrombin generation in paediatric patients with immune thrombocytopenia.

Clinical manifestations and laboratory parameters of haemostasis were investigated in 23 children with newly diagnosed immune thrombocytopenia (ITP) before and after intravenous immunoglobulin (IVIg) treatment. ITP patients with platelet counts of less than 20 × 10 /L and mild bleeding symptoms, graded by a standardized bleeding score (BS), were compared with healthy children with normal platelet counts and children with chemotherapy-related thrombocytopenia. Markers of platelet activation and platelet apoptosis in the absence and presence of platelet activators were analysed by flow cytometry; thrombin generation in plasma was determined.

Thromboelastography and thrombin generation assessments for pediatric severe hemophilia A patients are highly variable and not predictive of clinical phenotypes.

Background: Severe hemophilia A (SHA) patients vary in severity of bleeding, arthropathy, and requirements for replacement factor VIII (FVIII). Baseline hemostatic activity assays using calibrated automated thrombography (CAT) and thromboelastography (TEG) may offer insights into the physiological basis of clinical heterogeneity.

Objectives: Use CAT and TEG to measure baseline hemostatic activity in a cohort of 30 pediatric SHA patients with available clinical data.

Low-dose aspirin and rivaroxaban combination therapy to overcome aspirin non-sensitivity in patients with vascular disease.

Approximately 20% of vascular patients treated with acetyl salicylic acid (i.e., aspirin) demonstrate less than expected platelet inhibition - putting them at a four-fold increased risk of adverse cardiovascular events.

Moderate-intensity aerobic exercise vs desmopressin in adolescent males with mild hemophilia A: a randomized trial.

Persons with mild hemophilia A (HA) may use intranasal desmopressin prior to sports participation. Desmopressin is expensive and can cause vomiting, headache, palpitation, and occasionally seizures. Our group has previously documented a 2.

Novel cysteine substitution p.(Cys1084Tyr) causes variable expressivity of qualitative and quantitative VWF defects.

von Willebrand factor (VWF) is an extremely cysteine-rich multimeric protein that is essential for maintaining normal hemostasis. The cysteine residues of VWF monomers form intra- and intermolecular disulfide bonds that regulate its structural conformation, multimer distribution, and ultimately its hemostatic activity. In this study, we investigated and characterized the molecular and pathogenic mechanisms through which a novel cysteine variant p.

Aspirin nonsensitivity in patients with vascular disease: Assessment by light transmission aggregometry (aspirin nonsensitivity in vascular patients).

Background: Aspirin is a key antiplatelet therapy for the prevention of thrombotic events in patients with cardiovascular disease. Studies suggest that ≈20% of patients with cardiac disease suffer from aspirin nonsensitivity, a phenomenon characterized by the inability of 81 mg aspirin to inhibit platelet aggregation and/or prevent adverse cardiovascular events.

Objectives: To investigate aspirin nonsensitivity in patients with vascular disease and assess the consequences of aspirin nonsensitivity.

Plateletworks as a Point-of-Care Test for ASA Non-Sensitivity.

Aspirin (ASA) therapy is proven to be effective in preventing adverse cardiovascular events; however, up to 30% of patients are non-sensitive to their prescribed ASA dosage. In this pilot study, we demonstrated, for the first time, how ASA non-sensitivity can be diagnosed using Plateletworks, a point-of-care platelet function test. Patients prescribed 81 mg of ASA were recruited in a series of two successive phases-a discovery phase and a validation phase.

Bleeding Severity and Phenotype in 22q11.2 Deletion Syndrome-A Cross-Sectional Investigation.

Objectives: To prospectively quantify bleeding severity and elaborate hemorrhagic symptoms in children with 22q11.2 deletion syndrome (22q11DS) using 2 validated bleeding assessment tools (BATs), namely the Pediatric Bleeding Questionnaire and the International Society on Thrombosis and Hemostasis BAT (ISTH-BAT). We also sought to compare subjects' bleeding scores to unaffected first-degree family members.

A Practical, One-Clinic Visit Protocol for Pharmacokinetic Profile Generation with the ADVATE myPKFiT Dosing Tool in Severe Hemophilia A Subjects.

Standard pharmacokinetic (PK) assessments are demanding for persons with hemophilia A, requiring a 72-hour washout and 5 to 11 timed blood samples. A no-washout, single-clinic visit, sparse sampling population PK (PPK) protocol is an attractive alternative. Here, we compared PK parameters obtained with a traditional washout, 6-sampling time point PPK protocol with a no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol in persons with severe hemophilia A (SHA) receiving ADVATE.

Personalization of Aspirin Therapy Ex Vivo in Patients with Atherosclerosis Using Light Transmission Aggregometry.

Acetylsalicylic acid (ASA), also known as aspirin, appears to be ineffective in inhibiting platelet aggregation in 20-30% of patients. Light transmission aggregometry (LTA) is a gold standard platelet function assay. In this pilot study, we used LTA to personalize ASA therapy ex vivo in atherosclerotic patients.

Ticagrelor as an Alternative Antiplatelet Therapy in Cardiac Patients Non-Sensitive to Aspirin.

Aspirin (acetylsalicylic acid-ASA) is a first-line antiplatelet therapy provided to patients with coronary artery disease (CAD). However, it has been demonstrated that 20-30% of these patients are non-sensitive to their ASA therapy. ASA non-sensitivity is a phenomenon where low-dose ASA (81-325 mg) does not completely inhibit arachidonic-acid-induced platelet aggregation, putting patients at risk of adverse cardio-thrombotic events.

Altered coagulation profile in peripheral artery disease patients.

Objective: Peripheral artery disease patients have been shown to be more susceptible to thrombotic events compared to non-peripheral artery disease patients. Therefore, the aim of this study was to investigate the coagulation profile in peripheral artery disease patients with chronic limb threatening ischemia, moderate peripheral artery disease patients with claudication, and non-peripheral artery disease controls.

Methods: Chronic limb threatening ischemia patients were matched to peripheral artery disease patients with claudication and non-peripheral artery disease controls in a 1:1:1 ratio.

Increased levels of IL-10 and IL-1Ra counterbalance the proinflammatory cytokine pattern in acute pediatric immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disease which leads to accelerated platelet clearance. We investigated the plasma cytokine, chemokine and growth factor signatures and their clinical significance in pediatric ITP patients during acute, chronic and follow-up stages as well as the effects of intravenous immunoglobulin (IVIg) treatment, by using the Multiplex technology. In acute ITP before and/or after IVIg treatment we found significantly increased plasma levels of the pro- (tumour necrosis factor-α (TNF-α), interleukin IL-15) and anti- (IL-1 receptor antagonist (Ra), IL-10 and the growth factor interferon γ-induced protein (IP-10)) inflammatory cytokines, compared to healthy controls.

Procoagulant Phosphatidylserine-Exposing Platelets and .

The physiological heterogeneity of platelets leads to diverse responses and the formation of discrete subpopulations upon platelet stimulation. Procoagulant platelets are an example of such subpopulations, a key characteristic of which is exposure either of the anionic aminophospholipid phosphatidylserine (PS) or of tissue factor on the activated platelet surface. This review focuses on the former, in which PS exposure on a subpopulation of platelets facilitates assembly of the intrinsic tenase and prothrombinase complexes, thereby accelerating thrombin generation on the activated platelet surface, contributing importantly to the hemostatic process.

Bleeding assessment tools to predict von Willebrand disease: Utility of individual bleeding symptoms.

Background: Bleeding assessment is part of the diagnostic workup of von Willebrand disease (VWD). Bleeding assessment tools (BATs) have standardized obtaining this information but have been criticized because they are time consuming.

Objective: To use our legacy data to determine which questions from BATs are the strongest predictors of a VWD diagnosis.

Comparative pharmacokinetics of two extended half-life FVIII concentrates (Eloctate and Adynovate) in adolescents with hemophilia A: Is there a difference?

Unlabelled: Essentials The PK parameters of Eloctate vs Adynovate were compared using one-stage and chromogenic assays in 25 boys (12-18 years). The FVIII levels were taken at 3, 24, 48, and 72 hours following a dose of either FVIII; levels analyzed by WAPPS PK program. The PK profiles (half-life, clearance, and time to 5%, 3%, and 1%) were not statistically different for the two EHL FVIIIs.

Validation of the school age self-administered pediatric bleeding questionnaire (Self-PBQ) in children aged 8-12 years.

Background: In the pediatric population, pathologic bleeding is often challenging to identify. The pediatric bleeding questionnaire (PBQ) was developed as a screening tool for von Willebrand disease (VWD) but was designed to be self-completed by children above 12 years of age. The study objective was to determine whether a modified Self-PBQ could be completed by 8- to 12-year-old children with adult assistance.

Analysis of procoagulant phosphatidylserine-exposing platelets by imaging flow cytometry.

Background: Upon platelet activation, a subpopulation of procoagulant platelets is formed, characterized by the exposure of the anionic aminophospholipid phosphatidylserine (PS) on the surface membrane.

Objective: To evaluate procoagulant PS-exposing platelets by imaging flow cytometry.

Methods: Platelet ultrastructure was examined by transmission electron microscopy, and a comprehensive analysis of procoagulant platelets was performed using imaging flow cytometry; platelets were fluorescently labeled for the markers glycoprotein (GP)IX, activated integrin αIIbβ3, CD62P, and PS exposure.

Apolipoprotein A-IV binds αIIbβ3 integrin and inhibits thrombosis.

Platelet αIIbβ3 integrin and its ligands are essential for thrombosis and hemostasis, and play key roles in myocardial infarction and stroke. Here we show that apolipoprotein A-IV (apoA-IV) can be isolated from human blood plasma using platelet β3 integrin-coated beads. Binding of apoA-IV to platelets requires activation of αIIbβ3 integrin, and the direct apoA-IV-αIIbβ3 interaction can be detected using a single-molecule Biomembrane Force Probe.

Idiopathic pulmonary arterial hypertension - a unrecognized cause of high-shear high-flow haemostatic defects (otherwise referred to as acquired von Willebrand syndrome) in children.

Acquired von Willebrand syndrome (AVWS) is reported in high-flow high-shear congenital cardiac disorders. We hypothesized that the narrowed pulmonary vasculature in idiopathic pulmonary arterial hypertension (IPAH) may induce AVWS. We conducted a cross-sectional evaluation of children with IPAH.

Laboratory diagnosis of inherited platelet function disorders.

Platelets respond to vessel wall injury by forming a primary hemostatic plug to arrest blood loss. Hemostatic plug formation is complex, and involves platelet adhesion to the subendothelium that results in platelet activation and ultimately, aggregation. If any of these processes are deficient, primary hemostasis is impaired.