Tag Archives: thrombosis

Thrombosis and Inflammation Drive Mortality and Cancer Risk in Myeloproliferative Disorders

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November 15, 2024

Lisa Kuhns, PhD, MD

Despite the advancements in treatment, thrombosis remains a significant challenge for patients with myeloproliferative neoplasms (MPNs), contributing to increased mortality and the development of secondary cancers, according to an article published in Blood Cancer Journal.

“These risks arise from disease-related clonal hematopoiesis and subsequent chronic systemic inflammation, leading to thrombosis and genetic instability,” explained Tiziano Barbui, FROM, Fondazione per la Ricerca Ospedale di Bergamo ETS, Bergamo, Italy, and coauthors. “In our large databases of patients with MPN, we investigated the incidence and risk factors of thrombosis that may explain this association, culminating in an increased risk of mortality.”

Recent research has highlighted the persistent risk of thrombotic events in patients with classic MPNs, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These disorders are characterized by a high incidence of both arterial and venous thrombosis, which complicates patient management and contributes to disease progression. Notably, studies indicate that approximately 20% of MPN diagnoses are heralded by thrombotic events, with ongoing risks observed over time.

A large-scale study involving more than 9000 patients with MPN revealed significantly elevated hazard ratios for thrombotic events compared with matched controls. Specifically, arterial thrombosis hazard ratios were 3.0 at 3 months and 2.0 at 1 year postdiagnosis. Venous thrombosis rates were even more alarming, with hazard ratios of 9.7 at 3 months and 4.7 at 1 year. While conventional treatments such as hydroxyurea have demonstrated efficacy in reducing arterial thrombosis, their impact on venous events is less pronounced.

The implications of these findings extend beyond immediate health risks and suggest a potential link between thrombosis and progression to more severe forms of MPNs, such as myelofibrosis and acute leukemia. In particular, arterial thrombosis has been identified as an independent predictor of increased mortality in patients with ET and PV. For instance, a multistate model analysis indicated that patients experiencing arterial thrombosis had a 25% increase in mortality risk compared with those without such events.

Emerging evidence also suggests that thrombosis may be associated with an increased risk of developing secondary cancers in patients with MPN. A nested case-control study found that the occurrence of arterial thrombosis was independently linked to a higher incidence of secondary cancers, particularly among younger patients with MPNs. This correlation underscores the complex interplay between chronic inflammation induced by MPNs and the risk factors for both cardiovascular disease and cancer.

“We believe that arterial, and possibly venous thrombosis occurring during follow-up should be considered in the context of long-term occurring outcomes, including an increased incidence of solid tumors,” concluded the study authors.

Continued research is essential to unravel the underlying mechanisms linking thrombosis with disease progression and secondary malignancies, ultimately improving patient outcomes in this vulnerable population.

Reference

Barbui T, Ghirardi A, Carobbio A, et al. Thrombosis in myeloproliferative neoplasms: a viewpoint on its impact on myelofibrosis, mortality, and solid tumors. Blood Cancer J. 2024;14(1):188. doi:10.1038/s41408-024-01169-6

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Thrombosis in myeloproliferative neoplasms: a viewpoint on its impact on myelofibrosis, mortality, and solid tumors

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October 25, 2024

Tiziano Barbui, Arianna Ghirardi, Alessandra Carobbio, Valerio De Stefano, Alessandro Rambaldi, Ayalew Tefferi & Alessandro M. Vannucchi

Abstract

This viewpoint summarizes findings from analyses of large personal patient databases of myeloproliferative neoplasms (MPNs) to assess the impact of thrombosis on mortality, disease progression, and second cancers (SC). Despite advances, the current incidence of arterial and venous thrombosis remains a challenge. These events appear to signal a more aggressive disease course, as evidenced by their association with myelofibrosis progression and mortality using multistate models and time-dependent multivariable analysis. Inflammatory biomarkers, such as the neutrophil-to-lymphocyte ratio (NLR), are associated with the aggressiveness of polycythemia vera (PV) and essential thrombocythemia (ET), linking thrombosis to SC risk. This suggests a common inflammatory pathway likely influencing cardiovascular disease and cancer incidence. Notably, this is observed more frequently in younger patients, likely due to prolonged exposure to MPN and environmental inflammatory triggers. These data underscore the need for new studies to validate these associations, delineate the sequence of events, and identify therapeutic targets to mitigate thrombotic events and potentially improve overall patient outcomes in MPN.

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HTR1B Expression and Thrombosis in Patients With Myeloproliferative Neoplasms

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Vicki Moore, PhD

In this retrospective study, the researchers evaluated expression levels of HTR1B based on messenger RNA from peripheral blood mononuclear cells obtained from patients with newly diagnosed MPN, in addition to conducting other analyses. The researchers had a goal of evaluating possible differences in expression of this gene across MPN subtypes.

There were 85 patients with newly diagnosed MPN included in the analysis, with a median age of 57 years (range, 23-80). Among these patients, 28 had polycythemia vera (PV), 25 had essential thrombocythemia (ET), and 32 had primary myelofibrosis (PMF). Additionally, comparisons of HTR1B expression included 6 healthy volunteers.

Across MPN subtypes and control individuals, the expression of HTR1B did not significantly differ (P =.3089). However, there was large variation observed in expression levels. The researchers further examined expression levels in the context of other patient factors, including based on whether patients had a thrombotic or non-thrombotic history.

A total of 32 patients were considered to have thrombotic MPNs and 53 patients were considered to have nonthrombotic MPN, with median ages of 57 years in each group. Levels of HTR1B expression were significantly different when analyzed across groups organized by thrombotic MPN, nonthrombotic MPN, or status as control individuals.

The level of HTR1B expression appeared highest among patients with thrombotic MPNs, while levels appeared to not be significantly different between patients with nonthrombotic MPNs and control individuals. Among patients with thrombotic MPNs, there was no statistically significant difference observed in the level of fold-change in HTR1B expression by MPN subtype.

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Platelet proteomic profiling reveals potential mediators of immunothrombosis and proteostasis in myeloproliferative neoplasms

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August 14, 2024

Sarah Kelliher, Sara Gamba, Luisa Weiss, Zhu Shen, Marina Marchetti, Francesca Schieppati, Caitriona Scaife, Stephen Madden, Kathleen Bennett, Anne Fortune, Su Maung, Michael Fay, Fionnuala Ní Áinle, 
Patricia Maguire, Anna Falanga, Barry Kevane, Anandi Krishnan

Myeloproliferative neoplasms (MPNs) are chronic bone marrow malignancies characterized by clonal proliferation of hematopoietic precursors and elevated cell counts in peripheral blood.1 Patients with MPN are at risk of progression to myelofibrosis or acute leukemia and experience a substantial burden of microvascular symptoms.2,3 However, thrombosis (both arterial and venous) represents the leading cause of morbidity and mortality for patients with polycythemia vera (PV) and essential thrombocythemia (ET).4-6

Translational studies have indicated that the platelet proteome influences pathways relating to immune response, inflammation, and malignancy.7,8 Thrombocytosis and platelet hyperactivity are hallmarks of MPN;9 however, platelet count in isolation is not predictive of clinical outcome, and conventional antiplatelet therapy does not fully mitigate thrombotic risk.10 A comprehensive picture of the MPN platelet molecular profile is lacking, and to date, no studies have evaluated the unbiased platelet proteome in a sizable clinical cohort of affected patients. Here, we performed untargeted quantitative profiling of the platelet proteome in a large (n = 140) cohort of patients with PV and ET.

Using standardized platelet isolation protocols (supplemental Methods), we prepared purified platelets from peripheral blood samples of patients with an established diagnosis of MPN (World Health Organization defined, n = 59 ET, n = 41 PV) and a cohort of healthy controls (n = 40) recruited across 2 sites: Hospital Papa Giovanni XXIII, Bergamo, Italy and Mater Misericordiae University Hospital, Dublin, Ireland. Pertinent clinical features are shown in Figure 1 (and listed in supplemental Table 1). Interpatient variability, including age, sex, and treatment, as well as experimental batch effects, were adjusted as confounding factors in downstream expression analyses (supplemental Methods). Focusing on the most prothrombotic subtypes of MPNs, we hypothesized that the platelet proteome differs in MPN, and its characterization would offer insights into the underlying pathobiology and possible mechanisms underlying the associated clinical complications.

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High Neutrophil Ratio as a Thrombosis Predictor in Myeloproliferative Neoplasms

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July 24, 2024

The following is a summary of “Predictive significance of high neutrophil ratio for thrombosis in myeloproliferative neoplasms: JSH-MPN-R18 subanalysis,” published in the July 2024 issue of Hematology by Nagaharu et al.

A nationwide study was conducted to identify clinical features of thrombosis in patients with myeloproliferative neoplasms to inform risk-based treatment strategies.

Researchers conducted a retrospective study to determine which complete blood count (CBC) parameters predicted thrombosis in patients with myeloproliferative neoplasms.

They investigated patients from JSH-MPN-R18, focusing on essential thrombocythemia (ET; n = 1152) and polycythemia vera (PV; n = 456). Using Welch’s T-test, the CBC parameters were compared with those with or without thrombotic events. Statistical analyses were conducted with R software.

The results showed that 74 patients with ET experienced thrombotic events. In multivariate analysis, patients with ET and thrombosis had a slightly but significantly higher neutrophil ratio compared to those without thrombosis (P<0.05). The absolute neutrophil count (aNeu) emerged as a valuable predictor for thrombosis in patients with low-risk according to the revised International Prognostic Score of Thrombosis for ET. Among patients with PV, those with thrombosis had notably higher hematocrit and aNeu levels than those without thrombosis. Additionally, the neutrophil ratio was slightly but significantly higher in patients with ET with thrombosis, potentially reflecting a greater JAK2 V617F allelic frequency, though was not detailed in JSH-MPN-R18.

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A Review About the Assessment of the Bleeding and Thrombosis Risk for Patients With Myeloproliferative Neoplasms Scheduled for Surgery

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Mihaela Andreescu • Bogdan Andreescu

Published March 12, 2024

Abstract

Myeloproliferative neoplasms (MPNs) present a unique challenge in surgical management due to their inherent predisposition to both bleeding and thrombosis. MPNs are a heterogenous group of acquired clonal conditions. The three classic MPNs are essential thrombocythemia (ET), myelofibrosis (PMF), and polycythemia vera (PV). All subtypes of MPN are associated with both thrombotic and bleeding complications. There are four risk categories for thrombosis in MPN patients: age, thrombosis history, and JAK-2 mutation. They are further classified as very low, low, intermediate, and high risk. The genetic landscape of MPN is fascinating and complex like all myeloid disorders. Bleeding risk can be assessed through leukocytosis, thrombocytosis, acquired von Willebrand syndrome (AVWS), and a previous history of bleeding in a patient. Risk assessment and perioperative management are important aspects of improving the quality of life and preventing complications in surgeries. Preoperative management includes a risk assessment of venous thromboembolism, use of appropriate pharmacological treatment, platelet count control, and correction and cardiovascular risk factors. This review summarizes the assessment of bleeding and thrombosis risk for patients with MPNs scheduled for surgery. Furthermore, this review discusses various tools that can be used to identify MPN patients at risk of thrombosis prior to surgery.

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Red Blood Cell Contribution to Thrombosis in Polycythemia Vera and Essential Thrombocythemia

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Julien Grenier, Wassim El Nemer, and Maria De Grandis

Abstract

Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms (MPN) characterized by clonal erythrocytosis and thrombocytosis, respectively. The main goal of therapy in PV and ET is to prevent thrombohemorrhagic complications. Despite a debated notion that red blood cells (RBCs) play a passive and minor role in thrombosis, there has been increasing evidence over the past decades that RBCs may play a biological and clinical role in PV and ET pathophysiology. This review summarizes the main mechanisms that suggest the involvement of PV and ET RBCs in thrombosis, including quantitative and qualitative RBC abnormalities reported in these pathologies. Among these abnormalities, we discuss increased RBC counts and hematocrit, that modulate blood rheology by increasing viscosity, as well as qualitative changes, such as deformability, aggregation, expression of adhesion proteins and phosphatidylserine and release of extracellular microvesicles. While the direct relationship between a high red cell count and thrombosis is well-known, the intrinsic defects of RBCs from PV and ET patients are new contributors that need to be investigated in depth in order to elucidate their role and pave the way for new therapeutical strategies.