PB0096 - Microparticles and hemostasis of children with hemolysis

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Elena A. Seregina, PhD

Leading Researcher
Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia

Co-Author(s)

EL

Elena N. Lipets

Lead researcher, P.h.D.
Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
Alexander Poletaev

Head of the Laboratory of Clinical Hemostasis
Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
AI

Anastasia Ignatova

Research associate
Dmitry Rogachev National Medical Research Centеr of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
YC

Yaroslav M. Chuiko

Student of Pediatric Department
Pirogov Russian National Research Medical University
Moscow, Moskva, Russia
TV

Tatiana A. Vuimo

Leading researcher, P.h.D.
Center for Theoretical Problems of Physicochemical Pharmacology
Moscow, Moskva, Russia
FA

Fazoil I. Ataullakhanov

Dr.Sci.Biol., Head of Biophysics and Systems Biology Department
Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
NS

Nataliya S. Smetanina

Dr.Sci.Med.,Director of the Department for Scientific and Analytical Work with Regions, Hematologist
Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia

Background: Patients with hemolysis have the risk for thrombosis. Procoagulant microparticles derived from the breaking down RBC.

Aims: The aim of this study was study the mechanism of microparticles contribution on the hypercoagulation in patients with hemolysis.

Methods: The hemostasis of 26 children (14 boys, age: 3-17 yrs): 16 with hereditary spherocytosis (HS) and 10 with β-thalassemia(β-TM) was described using clotting times, fibrinogen, D-dimer and thrombodynamics(TD) global hemostasis assay. The count of microparticles was assessed by flow cytometry. Eight healthy donors were enrolled as a control group.

Results: Patients were divided into two groups: 8 with mild disease and 18 with severe disease. Clotting times were in normal range for all patients but TD clot growth rate was increased in 17 children(59,2±3,56µm/min) with severe disease and slightly increase in 1 patient(56,6µm/min) with mild disease compared to normal range 38-56µm/min. The patients with severe disease have the increased clot growth rates in 94% and highest concentration of phosphatidylserine-exposing microparticles(PS+MP) marked by annexin V(binds to the phosphatidylserine) in flow cytometry (1814±817 PS+MP/μl, normal range 300-600 PS+MP/μl). The patients with mild disease have nearly 2 times lower counts of the procoagulant microparticles (606±166 PS+MP/μl). Glycophorin-exposing(CD235a+MP) microparticles were identified as derived from RBC. The patients with highest spatial clot growth rates have the highest RBC-derived micropaticles count. To evaluate the procoagulant properties of microparticles: they were titrated in a purified from microparticles plasma mixture of healthy donors. We’ve observed that at the same concentrations the contribution of microparticles to the clot growth rate is the same for donors and patients with hemolysis.

Conclusion(s): The highest counts of procoagulant microparticles were in patients with highest hypercoagulation by clot growth rates. Using microparticles titration in purified plasma of healthy donors, we determined that at the same concentrations the microparticles of patients and donors affect the clot growth rate the same way.