PB0272 - The role of procoagulant microparticles in hemostasis of patients with hemolysis

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Elena A. Seregina, phD

research associate
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia

Co-Author(s)

EL

Elena N. Lipets

research associate
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
Aleksander Poletaev

Head of laboratory
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
AI

Anastasia A. Ignatova

Researcher
Dmitry Rogachev National Medical Research Center Of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
YC

Yaroslav M. Chuiko

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

Tatiana A. Vuimo

lead researcher
Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
FA

Fazoil I. Ataullakhanov

head of Biophysics and Systems Biology department
Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia
NS

Nataliya S. Smetanina

the head of the Scientific and Analytical Work department
Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology
Moscow, Moskva, Russia

Background: Patients with hemolytic anemias are characterized by the increased risk for thrombosis. More and more studies have reported about procoagulant microparticles derived from the cells during hemolysis.

Aims: The aim of this study was to assess the contribution of procoagulant microparticles to the hypercoagulation in patients with hemolytic anemias.

Methods: The hemostasis of 5 children (boys, age: 4-12 yrs, girl 5 yr) with hereditary spherocytosis (HS) and 8 children with β-thalassemia major(β-TM) (2 girls 8 and 17 yrs, and 6 boys 2-15 yrs) was described using clotting times (APTT, PT), fibrinogen and D-dimer levels and thrombodynamics (TD) global hemostasis assay. The count of microparticles was assessed by flow cytometry. Five healthy donors were enrolled as a control group.

Results: Clotting times were normal in all patients but TD clot growth rate was increased in 7 children compared to normal range (59±2 µm/min for TD initial clot growth rate with normal range 38-56 µm/min). All patients with hypercoagulation were in severe condition: 3 patients with β-TM have no remission after splenectomy. The patients with high clot growth rates have the highest concentrations of phosphatidylserine-exposing microparticles(PS+MP) identified as procoagulant (1747±631 PS+MP/μl with normal range 306-606 PS+MP/μl). The patients without hypercoagulation have nearly 2 times lower counts of the procoagulant microparticles (740±378 PS+MP/μl). Glycophorin-exposing(CD235a+MP) microparticles were identified as erythrocyte-derived. Erythrocyte-derived microparticles were the highest in patients with the changes in the spatial dynamics of clot growth: an increase in stationary clot growth rate measured after fibrin layer was closed the activator surface with tissue factor.

Conclusion(s): Hypercoagulation was observed in patients with hemolysis in severe condition. The highest counts of procoagulant microparticles were in patients with hypercoagulation by clot growth rates. The highest counts erythrocyte-derived microparticles were revealed in patients with the disturbance of spatial dynamics of clot growth.