Publications by authors named "Stephanie E Reitsma"

Article Synopsis
  • Bleeding disorder of unknown cause (BDUC) is diagnosed after ruling out other causes, and this study analyzed data from 375 BDUC patients compared to 100 healthy controls.
  • The findings revealed that BDUC patients had lower peak plasmin levels and clot density, indicating potential issues with clot structure, while still showing a higher potential for plasmin generation.
  • A model including fibrinogen and plasmin generation parameters effectively distinguished BDUC patients from healthy controls, demonstrating the potential for predictive diagnostics in bleeding disorders.
View Article and Find Full Text PDF
Article Synopsis
  • * In a study of 86 ITP patients and 78 healthy controls, findings showed that ITP patients had significantly slower clot lysis times and higher levels of plasminogen activator inhibitor-1 (PAI-1), while tissue plasminogen activator (tPA) levels were lower.
  • * The results suggest that prolonged clot lysis time (CLT) and altered fibrinolysis mechanisms in ITP may contribute to thrombosis risk, with specifically higher tPA-PAI-1 complexes indicating potential
View Article and Find Full Text PDF

Background: Postpartum hemorrhage is difficult to predict, is associated with significant maternal morbidity, and is the leading cause of maternal mortality worldwide. The identification of maternal biomarkers that can predict increased postpartum hemorrhage risk would enhance clinical care and may uncover mechanisms that lead to postpartum hemorrhage.

Objective: This retrospective case-control study employed agnostic proteomic profiling of maternal plasma samples to identify differentially abundant proteins in controls and postpartum hemorrhage cases.

View Article and Find Full Text PDF

Background: Factor (F) XI deficiency is associated with increased bleeding risk in some individuals. Neither FXI levels nor clinical clotting assays predict the bleeding risk. Compared with controls, FXI-deficient bleeders have reduced clot formation, decreased fibrin network density, and increased susceptibility to fibrinolysis.

View Article and Find Full Text PDF
Article Synopsis
  • LDL plays a significant role in cardiovascular disease, particularly through its interaction with platelets, but the specific mechanisms and effective therapeutic strategies are not well understood.
  • This study focuses on how oxidized LDL (oxLDL) increases platelet activation via the glycoprotein VI (GPVI) pathway and assesses the impact of various antiplatelet therapies on this process.
  • The findings indicate that oxLDL boosts platelet activity and procoagulant responses more effectively reduced by purinergic receptor antagonists and tyrosine kinase inhibitors, rather than traditional COX inhibitors like aspirin.
View Article and Find Full Text PDF

Tyrosine kinase inhibitors (TKIs) have emerged as a promising class of target-directed, small molecule inhibitors used to treat hematologic malignancies, inflammatory diseases, and autoimmune disorders. Recently, TKIs have also gained interest as potential antiplatelet-directed therapeutics that could be leveraged to reduce pathologic thrombus formation and atherothrombotic complications, while minimally affecting platelet hemostatic function. This review provides a mechanistic overview and summarizes the known effects of tyrosine kinase inhibitors on platelet signaling and function, detailing prominent platelet signaling pathways downstream of the glycoprotein VI (GPVI) receptor, integrin αβ, and G protein-coupled receptors (GPCRs).

View Article and Find Full Text PDF

Background: Biochemical reaction networks are self-regulated in part due to feedback activation mechanisms. The tissue factor (TF) pathway of blood coagulation is a complex reaction network controlled by multiple feedback loops that coalesce around the serine protease thrombin.

Objectives: Our goal was to evaluate the relative contribution of the feedback activation of coagulation factor XI (FXI) in TF-mediated thrombin generation using a comprehensive systems-based analysis.

View Article and Find Full Text PDF

Cannabis usage has steadily increased as acceptance is growing for both medical and recreational reasons. Medical cannabis is administered for treatment of chronic pain based on the premise that the endocannabinoid system signals desensitize pain sensor neurons and produce anti-inflammatory effects. The major psychoactive ingredient of cannabis is Δ9-tetrahydrocannabinol (THC) that signals mainly through cannabinoid receptor-1 (CBr), which is also present on nonneuron cells including blood platelets of the circulatory system.

View Article and Find Full Text PDF

Circulating platelets establish a variety of immunological programs and orchestrate inflammatory responses at the endothelium. Platelets express the innate immunity family of Toll-like receptors (TLRs). While TLR2/TLR1 ligands are known to activate platelets, the effects of TLR2/TLR6 ligands on platelet function remain unclear.

View Article and Find Full Text PDF

Several Janus kinase (JAK) inhibitors (jakinibs) have recently been approved to treat inflammatory, autoimmune and hematological conditions. Despite emerging roles for JAKs and downstream signal transducer and activator of transcription (STAT) proteins in platelets, it remains unknown whether jakinibs affect platelet function. Here, we profile platelet biochemical and physiological responses in the presence of five different clinically relevant jakinibs, including ruxolitinib, upadacitinib, oclacitinib, baricitinib and tofacitinib.

View Article and Find Full Text PDF

Complement factor H (CFH) is the major inhibitor of the alternative pathway of the complement system and is structurally related to beta2-glycoprotein I, which itself is known to bind to ligands, including coagulation factor XI (FXI). We observed reduced complement activation when FXI activation was inhibited in a baboon model of lethal systemic inflammation, suggesting cross-talk between FXI and the complement cascade. It is unknown whether FXI or its activated form, activated FXI (FXIa), directly interacts with the complement system.

View Article and Find Full Text PDF

Factor XI (FXI) has been shown to bind platelets, but the functional significance of this observation remains unknown. Platelets are essential for hemostasis and play a critical role in thrombosis, whereas FXI is not essential for hemostasis but promotes thrombosis. An apparent functional contradiction, platelets are known to support thrombin generation, yet platelet granules release protease inhibitors, including those of activated FXI (FXIa).

View Article and Find Full Text PDF

Background: Human coagulation factor (F) XI deficiency, a defect of the contact activation system, protects against venous thrombosis, stroke, and heart attack, whereas FXII, plasma prekallikrein, or kininogen deficiencies are asymptomatic. FXI deficiency, inhibition of FXI production, activated FXI (FXIa) inhibitors, and antibodies to FXI that interfere with FXI/FXII interactions reduce experimental thrombosis and inflammation. FXI inhibitors are antithrombotic in patients, and FXI and FXII deficiencies are atheroprotective in apolipoprotein E-deficient mice.

View Article and Find Full Text PDF

Objective- Terminal complications of bacterial sepsis include development of disseminated intravascular consumptive coagulopathy. Bacterial constituents, including long-chain polyphosphates (polyP), have been shown to activate the contact pathway of coagulation in plasma. Recent work shows that activation of the contact pathway in flowing whole blood promotes thrombin generation and platelet activation and consumption distal to thrombus formation ex vivo and in vivo.

View Article and Find Full Text PDF

Platelet apheresis units are transfused into patients to mitigate or prevent bleeding. In a hospital, platelet apheresis units are transported from the transfusion service to the healthcare teams via two methods: a pneumatic tubing system (PTS) or ambulatory transport. Whether PTS transport affects the activity and utility of platelet apheresis units is unclear.

View Article and Find Full Text PDF

Based on their mechanisms-of-action, CD20 monoclonal antibodies (mAbs) are grouped into Type I [complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC)] and Type II [programmed cell death (PCD) and ADCC] mAbs. We generated 17 new hybridomas producing CD20 mAbs of different isotypes and determined unique heavy and light chain sequence pairs for 13 of them. We studied their epitope binding, binding kinetics and structural properties and investigated their predictive value for effector functions, i.

View Article and Find Full Text PDF

Platelet recruitment to sites of vascular injury is mediated by von Willebrand factor (VWF). The shear-induced unraveling of ultra-large VWF multimers causes the formation of a "stringlike" conformation, which rapidly recruits platelets from the bloodstream. A disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) regulates this process by cleaving VWF to prevent aberrant platelet adhesion; it is unclear whether the activity of ADAMTS13 itself is regulated.

View Article and Find Full Text PDF