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Ilich A, Gernsheimer TB, Triulzi DJ, Herren H, Brown SP, Holle LA, Lucas AT, de Laat B, El Kassar N, Wolberg AS, May S, Key NS. Absence of hyperfibrinolysis may explain lack of efficacy of tranexamic acid in hypoproliferative thrombocytopenia. Blood Adv 2023; 7:900-908. [PMID: 36044391 PMCID: PMC10025092 DOI: 10.1182/bloodadvances.2022008255] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/29/2022] [Accepted: 08/21/2022] [Indexed: 11/20/2022] Open
Abstract
The American Trial Using Tranexamic Acid (TXA) in Thrombocytopenia (A-TREAT, NCT02578901) demonstrated no superiority of TXA over placebo in preventing World Health Organization (WHO) grade 2 or higher bleeding in patients with severe thrombocytopenia requiring supportive platelet transfusion following myeloablative therapy for hematologic disorders. In this ancillary study, we sought to determine whether this clinical outcome could be explained on the basis of correlative assays of fibrinolysis. Plasma was collected from A-TREAT participants (n = 115) before the initiation of study drug (baseline) and when TXA was at steady-state trough concentration (follow-up). Global fibrinolysis was measured by 3 assays: euglobulin clot lysis time (ECLT), plasmin generation (PG), and tissue-type plasminogen activator (tPA)-challenged clot lysis time (tPA-CLT). TXA was quantified in follow-up samples by tandem mass spectrometry. Baseline samples did not demonstrate fibrinolytic activation by ECLT or tPA-CLT. Furthermore, neither ECLT nor levels of plasminogen activator inhibitor-1, tPA, plasminogen, alpha2-antiplasmin, or plasmin-antiplasmin complexes were associated with a greater risk of WHO grade 2+ bleeding. TXA trough concentrations were highly variable (range, 0.7-10 μg/mL) and did not correlate with bleeding severity, despite the fact that plasma TXA levels correlated strongly with pharmacodynamic assessments by PG (Spearman r, -0.78) and tPA-CLT (r, 0.74). We conclude that (1) no evidence of fibrinolytic activation was observed in these patients with thrombocytopenia, (2) trough TXA concentrations varied significantly between patients receiving the same dosing schedule, and (3) tPA-CLT and PG correlated well with TXA drug levels.
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Affiliation(s)
- Anton Ilich
- Division of Hematology, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
- UNC Blood Research Center, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Terry B. Gernsheimer
- Department of Medicine/Hematology and Seattle Cancer Care Alliance, University of Washington, Seattle, WA
| | | | - Heather Herren
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Siobhan P. Brown
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Lori A. Holle
- UNC Blood Research Center, University of North Carolina School of Medicine, Chapel Hill, NC
- Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Andrew T. Lucas
- Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC
| | - Bas de Laat
- Synapse Research Institute, Maastricht, The Netherlands
| | - Nahed El Kassar
- Division of Blood Diseases and Resources, National Heart Lung and Blood Institute, Washington, DC
| | - Alisa S. Wolberg
- UNC Blood Research Center, University of North Carolina School of Medicine, Chapel Hill, NC
- Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Susanne May
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Nigel S. Key
- Division of Hematology, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
- UNC Blood Research Center, University of North Carolina School of Medicine, Chapel Hill, NC
- Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, NC
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A rare coding mutation in the MAST2 gene causes venous thrombosis in a French family with unexplained thrombophilia: The Breizh MAST2 Arg89Gln variant. PLoS Genet 2021; 17:e1009284. [PMID: 33465109 PMCID: PMC7846112 DOI: 10.1371/journal.pgen.1009284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 01/29/2021] [Accepted: 11/18/2020] [Indexed: 11/19/2022] Open
Abstract
Rare variants outside the classical coagulation cascade might cause inherited thrombosis. We aimed to identify the variant(s) causing venous thromboembolism (VTE) in a family with multiple relatives affected with unprovoked VTE and no thrombophilia defects. We identified by whole exome sequencing an extremely rare Arg to Gln variant (Arg89Gln) in the Microtubule Associated Serine/Threonine Kinase 2 (MAST2) gene that segregates with VTE in the family. Free-tissue factor pathway inhibitor (f-TFPI) plasma levels were significantly decreased in affected family members compared to healthy relatives. Conversely, plasminogen activator inhibitor-1 (PAI-1) levels were significantly higher in affected members than in healthy relatives. RNA sequencing analysis of RNA interference experimental data conducted in endothelial cells revealed that, of the 13,387 detected expressed genes, 2,354 have their level of expression modified by MAST2 knockdown, including SERPINE1 coding for PAI-1 and TFPI. In HEK293 cells overexpressing the MAST2 Gln89 variant, TFPI and SERPINE1 promoter activities were respectively lower and higher than in cells overexpressing the MAST2 wild type. This study identifies a novel thrombophilia-causing Arg89Gln variant in the MAST2 gene that is here proposed as a new molecular player in the etiology of VTE by interfering with hemostatic balance of endothelial cells.
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