PB0954 - Endothelial dysfunction in myeloproliferative neoplasms debuting with splanchnic vein thrombosis

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Blanca De Moner Rafel, PhD Student (she/her/hers)

PhD student
Josep Carreras Leukaemia Research Institute, Hospital Clínic de Barcelona
Barcelona, Catalonia, Spain

Co-Author(s)

Julia Martinez-Sanchez, PhD

PhD student
Hemostasis and Erythropathology Laboratory, Hematopathology, Department of Pathology, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain.
Barcelona, Catalonia, Spain
HV

Helena Ventosa-Capell

MD, PhD Student
Hematopathology, Department of Pathology, Centre de Diagnostic Biomedic (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
Barcelona, Catalonia, Spain
Ana Belén Moreno-Castaño, MD

Medical Doctor
Hemostasis and Erythropathology Laboratory, Hematopathology, Department of Pathology, Centre de Diagnòstic Biomèdic (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain.
Barcelona, Catalonia, Spain
GE

Gines Escolar

MD PhD Senior Consultant
Hemostasis and Erythropathology Laboratory, Hematopathology, Department of Pathology, Centre de Diagnòstic Biomèdic (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain.
Barcelona, Catalonia, Spain
EC

Enric Carreras

Medical Doctor
Josep Carreras Leukaemia Research Institute, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain.
Barcelona, Catalonia, Spain
EA

Eduardo Arellano-Rodrigo

MD
Hematology Department, Institute of Haematology and Oncology, Hospital Clínic de Barcelona, IDIBAPS, Barcelona, Spain
Barcelona, Catalonia, Spain
AA

Alberto Alvarez-Larran

MD
Hematology Department, Institute of Haematology and Oncology, Hospital Clínic de Barcelona, IDIBAPS, Barcelona, Spain
Barcelona, Catalonia, Spain
MD

Maribel Diaz-Ricart

PhD Senior Consultant
Hemostasis and Erythropathology Laboratory, Hematopathology, Department of Pathology, Centre de Diagnòstic Biomèdic (CDB), Hospital Clínic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain.
Barcelona, Catalonia, Spain

Background: Myeloproliferative neoplasms (MPNs) JAK2V617F+ are characterized by abnormal proliferation of bone marrow progenitors and increased risk of thrombosis, specifically with splanchnic vein thrombosis.

Aims: To evaluate if endothelial dysfunction could contribute to the development of the associated thrombotic events.

Methods: Cultured endothelial cells (HMEC1) (EC) were exposed to serum from MPNs JAK2V617F+ patients with history of Bud-Chiari Syndrome/portal vein thrombosis (BCS/PVT), and from healthy donors (control, C). Changes in markers of inflammation (ICAM-1 expression), cell permeability (VE-cadherin expression), VWF production, and activation of stress and proliferation pathways (P-Akt, P-p44/42) were assessed by immunofluorescence, SDS-PAGE and immunoblot. Plasma VWF levels were measured using a coagulometer, and platelet adhesion to the extracellular matrix (ECM) was evaluated using perfusion chambers. Patients were classified according to treatment: Ruxolitinib (RX, n=8), Hydroxyurea (HU, n=4), Peg-Interferon (IFN, n=3), or no-treatment (NT, n=4).

Results: EC exposure to sera resulted in: increased ICAM-1 expression in HU, IFN and NT (2.53±0.47, 1.97±0.37, 1.38±0.10-fold p< 0.05), decreased VE-cadherin expression in RX and HU, (0.64±0.05, 0.62±0.08-fold, p< 0.05), and increased production and secretion of VWF to the ECM in all groups (RX=2.07±0.49-fold, HU=1.62±0.19-fold, IFN=1.74±0.12-fold, NT=2.23±0.38-fold p< 0.05), vs. C. Akt and p44/42 phosphorylation was higher in response to NT serum after 15 min (13.40±1.9-fold and 3.50±0.5-fold vs. C, p< 0.05). VWF plasma levels were above the reference values in all groups (VWF:Ag of 210.1±18.5Ul/dL; VWF:CoR of 187.1±16.9Ul/dL; FVIII of 149.8±10.1Ul/dL). Perfusion studies resulted in higher platelet adhesion on ECM in response to NT serum, vs. C (1.15±0.05-fold vs. C, p< 0.05).

Conclusion(s): Circulating humoral factors in MPNs with SVT debut induce a proinflammatory and prothrombotic state on the endothelium, independently of the treatment received, being superior in those without treatment. Future studies are needed to clarify the role of the endothelium in MPN-associated thrombosis, as well as its potential role as a therapeutic target.