PB0517 - Enhancement of experimental venous thrombosis in sickle trait mice is prevented by Gardos channel inhibition.

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Steven P. Grover, PhD

Research Assistant Professor
Division of Hematology and Blood Research Center, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States

Co-Author(s)

FT

Fatima Trebak

Postdoc
Division of Hematology and Blood Research Center, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States
Anton Ilich, MD

Research Associate
Division of Hematology and Blood Research Center, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States
YP

Yuriy Prokopenko

Postdoc
Division of Hematology and Blood Research Center, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States
ES

Erica M. Sparkenbaugh, PhD (she/her/hers)

Assistant Professor of Medicine
Division of Hematology and Blood Research Center, University of North Carolina, Chapel Hill
Chapel Hill, North Carolina, United States
MK

Malgorzata Kasztan

Assistant Professor
University of Alabama at Birmingham
Birmingham, Alabama, United States
NK

Nigel S. Key

Harold R. Roberts Distinguished Professor
Division of Hematology, University of North Carolina, Chapel Hill, NC, USA
Chapel Hill, North Carolina, United States
Rafal Pawlinski, PhD

Professor of Medicine
Division of Hematology and Blood Research Center, University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States

Background: Individuals with sickle cell trait (SCT) are heterozygous carriers of the sickle beta-globin gene. SCT is a known risk factor for venous thrombosis (VT), but the mechanism accounting for this complication is poorly understood.

Aims: To test whether sickling of SCT red blood cells (RBCs), triggered by exposure to prolonged severe hypoxia within venous thrombi, induces RBC-dependent procoagulant changes that contribute to VT.

Methods: VT was induced by complete occlusion (stasis) of the inferior vena cava (IVC) in humanized, control mice expressing two copies of normal hemoglobin beta globin (AA) or heterozygous for mutated sickle hemoglobin beta globin (AS). Senicapoc, an oral Gardos channel inhibitor, was administered twice daily (20mg/kg) for 2 weeks to prevent RBC dehydration and subsequent sickling in AS mice.

Results: Similar to individuals with SCT, blood cell counts in AS mice did not differ from AA controls. Basal plasma thrombin-antithrombin complex levels were also not different between AA and AS mice. Histologic evaluation demonstrated that severe hypoxia (pO2 ≈ 10 mm Hg) present in the nidus of venous thrombi was associated with sickled RBCs in AS mice. The weight of thrombi formed 24 hours after IVC stasis was significantly increased (p < 0.01) in AS mice (mean+/-SEM; 29.0 mg +/- 1.7; n=8) compared to AA controls (20.0 mg +/- 1.7; n=7). To determine if the enhancement of VT observed in AS mice was mediated by RBC sickling, mice were pretreated with Senicapoc or vehicle. Compared to vehicle-treated AS mice (27.3 mg +/- 2.2 n=9) pre-treatment with Senicopac significantly reduced (p < 0.05) clot weight (18.1mg +/- 1.1; n=7) to that observed in untreated AA controls.

Conclusion(s): We have established a mouse model of the venous thrombotic complications associated with SCT, and have demonstrated that hypoxia-induced sickling of RBCs contributes to enhanced VT observed in AS mice.