FXa takes center stage in vascular inflammation

Blood ◽  
2014 ◽  
Vol 123 (11) ◽  
pp. 1630-1631 ◽  
Author(s):  
Wolfram Ruf

In this issue of Blood, Sparkenbaugh et al identify coagulation factor Xa (FXa), the target for new protease-selective oral anticoagulants, as a crucial mediator for both coagulation abnormalities and chronic vascular inflammation that characterize sickle cell disease.1

2019 ◽  
Vol 3 (20) ◽  
pp. 3170-3180 ◽  
Author(s):  
Md Nasimuzzaman ◽  
Punam Malik

AbstractSickle cell disease (SCD) is an inherited monogenic red blood cell disorder affecting millions worldwide. SCD causes vascular occlusions, chronic hemolytic anemia, and cumulative organ damage such as nephropathy, pulmonary hypertension, pathologic heart remodeling, and liver necrosis. Coagulation system activation, a conspicuous feature of SCD that causes chronic inflammation, is an important component of SCD pathophysiology. The key coagulation factor, thrombin (factor IIa [FIIa]), is both a central protease in hemostasis and thrombosis and a key modifier of inflammation. Pharmacologic or genetic reduction of circulating prothrombin in Berkeley sickle mice significantly improves survival, ameliorates vascular inflammation, and results in markedly reduced end-organ damage. Accordingly, factors both upstream and downstream of thrombin, such as the tissue factor–FX complex, fibrinogen, platelets, von Willebrand factor, FXII, high-molecular-weight kininogen, etc, also play important roles in SCD pathogenesis. In this review, we discuss the various aspects of coagulation system activation and their roles in the pathophysiology of SCD.


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Erica M Sparkenbaugh ◽  
Kasemsiri Chandarajoti ◽  
Nigel S Key ◽  
Andras Gruber ◽  
Nigel Mackman ◽  
...  

Sickle cell disease (SCD) is associated with activation of coagulation and vascular inflammation. We previously demonstrated that, in mouse models of SCD, tissue factor (TF) expressed on leukocytes activates coagulation and contributes to inflammation via microvascular thrombosis, whereas non-coagulant form of TF expressed by endothelial cells mediates factor Xa (FXa)-PAR2 signalling and contributes to inflammation via IL-6 expression. We also showed that both rivaroxaban and dabigatran, oral inhibitors of FXa and thrombin, attenuated the hypercoagulable state in sickle mice. It has been proposed that anticoagulants that target the intrinsic coagulation pathway may be associated with a lower risk of bleeding compared to targeting the extrinsic or common coagulation pathways. Therefore, we tested if the intrinsic pathway contributes to the activation of coagulation in sickle cell mice. Bone marrow from sickle (SS) and non-sickle (AA) Townes mice was transplanted into wild-type (WT) (n=18 AA, 15 SS), FXII-/- (n=14 AA, 22 SS), or FXI-/- (n=21 AA, 23 SS) recipients (all on C57Bl/6 genetic background). In addition, bone marrow from AA or SS mice was transplanted into high molecular weight kininogen (HK)+/+ (n=17 AA, 16 SS) or HK-/- (n=10 AA, 19 SS) mice. All mice were used for experiments 5 months after BMT. Thrombin generation, measured by plasma thrombin anti-thrombin (TAT) levels, was increased in WT mice injected with SS bone marrow (WT/BMSS) compared to WT/BMAA mice (4.4±0.7 vs 2.6±0.3 ng/mL, p<0.05, mean ± S.E.M), however neither FXII nor FXI deficiency affected this parameter. Consistent with these data, inhibition of FXIIa-dependent activation of FXI with 14E11 antibody also did not reduce plasma TAT levels in SS Townes mice. Interestingly, elevated plasma TAT levels observed in HK+/+/BMSS mice was significantly reduced in HK-/-/BMSS mice (4.8±0.5 versus 3.48±0.2 ng/mL, p<0.05). These data indicate that HK, but not FXII and FXI, contributes to thrombin generation in SCD at steady state of disease. In vitro, HK fragments induce TF expression on monocytes via activation of CD11b/18. We are now investigating if inhibition of HK fragments-induced TF expression on monocytes may attenuate the hypercoagulabIe state in SCD mice without impacting hemostasis.


Blood ◽  
2012 ◽  
Vol 120 (3) ◽  
pp. 636-646 ◽  
Author(s):  
Pichika Chantrathammachart ◽  
Nigel Mackman ◽  
Erica Sparkenbaugh ◽  
Jian-Guo Wang ◽  
Leslie V. Parise ◽  
...  

Abstract Sickle cell disease (SCD) is associated with a complex vascular pathophysiology that includes activation of coagulation and inflammation. However, the crosstalk between these 2 systems in SCD has not been investigated. Here, we examined the role of tissue factor (TF) in the activation of coagulation and inflammation in 2 different mouse models of SCD (BERK and Townes). Leukocytes isolated from BERK mice expressed TF protein and had increased TF activity compared with control mice. We found that an inhibitory anti-TF antibody abrogated the activation of coagulation but had no effect on hemolysis or anemia. Importantly, inhibition of TF also attenuated inflammation and endothelial cell injury as demonstrated by reduced plasma levels of IL-6, serum amyloid P, and soluble vascular cell adhesion molecule-1. In addition, we found decreased levels of the chemokines MCP-1 and KC, as well as myeloperoxidase in the lungs of sickle cell mice treated with the anti-TF antibody. Finally, we found that endothelial cell-specific deletion of TF had no effect on coagulation but selectively attenuated plasma levels of IL-6. Our data indicate that different cellular sources of TF contribute to activation of coagulation, vascular inflammation, and endothelial cell injury. Furthermore, it appears that TF contributes to these processes without affecting intravascular hemolysis.


Blood ◽  
2014 ◽  
Vol 123 (11) ◽  
pp. 1747-1756 ◽  
Author(s):  
Erica M. Sparkenbaugh ◽  
Pichika Chantrathammachart ◽  
Jacqueline Mickelson ◽  
Joanne van Ryn ◽  
Robert P. Hebbel ◽  
...  

Key Points Inhibition of FXa or thrombin might be considered to reduce thrombotic complications and vascular inflammation in sickle cell patients. PAR-2 could be a potential target to inhibit vascular pathology associated with sickle cell disease.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4188-4188
Author(s):  
Waail Rozi Kashgary ◽  
Elrazi Awadelkarim Awadelkarim Hamid Ali ◽  
Alaa Rahhal ◽  
Abdulrahman F Al-Mashdali ◽  
Yousef Hailan ◽  
...  

Abstract Introduction: Sickle Cell Disease (SCD) is a hemolytic disorder with an increased risk of venous thromboembolism (VTE). By the age of 40 years around 11-12% of sickle cell disease patients will have at least one episode of VTE. VTE among patients with SCD is associated with a two to four times increase in mortality compared to SCD patients without VTE. Nevertheless, the evidence guiding VTE management in SCD, specifically in terms of anticoagulant choice, is scarce. Therefore, we conducted a systematic review that evaluates the effectiveness and safety of direct oral anticoagulants (DOACs) in SCD with VTE. Methods: We performed a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched the English literature (PubMed, SCOPUS, and Google Scholar) for randomized controlled trials, observational studies, reviews, case series, and case reports for patients with SCD treated with DOAC for thromboembolic disease. We used the terms in combination: "Sickle cell disease" or "Sickle cell anemia", and "DOAC", "rivaroxaban", "apixaban", "dabigatran" "edoxaban". The search included all articles published up to 20th April 2021. Quality and risk of bias assessment were done by two independent authors for each included study. Results: A total of 7 articles were included; four observational studies, and three case series addressing this matter. Patel A et al. found that the use of DOACs, including rivaroxaban, dabigatran, and apixaban in comparison to vitamin K antagonists (VKAs) and low molecular weight heparin (LMWH) for the treatment of VTE in SCD among adults was associated with similar VTE recurrence rate and a better safety profile in terms of a significant reduction in major bleeding events. Similarly, Roberts MZ et al. reported that the use of DOACs for VTE treatment in SCD compared to VKAs resulted in similar effectiveness in terms of VTE recurrence, but the use of DOACs was associated with a similar safety in comparison to VKAs in contrary to the results reported by Patel A et al. in their retrospective study. With regards to the risk of major hemorrhagic events associated with the use of non-VKAs, Gupta VK et al. showed that among 55 patients with SCD treated with VKAs, DOACs, or injectable anticoagulants, only patients treated with VKAs had major bleeding events. Discussion: The current data demonstrated that the use of DOACs for VTE in SCD has similar effectiveness in the prevention of VTE recurrence in comparison to other anticoagulants, including VKAs and injectable anticoagulants with a better safety profile. However, given the absence of clinical practice guidelines for the treatment of VTE among patients with SCD, the clinical practice guidelines recommendations for VTE treatment can be applied to patients with SCD. According to the latest CHEST guidelines (2016) for the treatment of VTE, the use of DOACs is recommended in patients with VTE over VKAs. Similarly, the latest American Society of Hematology (2020) guidelines for VTE suggest the use of DOACs over VKAs, except among patients with renal insufficiency (creatinine clearance less than 30 mL/min), moderate to severe liver disease, or those with antiphospholipid syndrome. Conclusion: In view of the current evidence and based on the results observed; using DOACs was associated with lesser bleeding incidence and fewer complications comparing to VKAs. We think it is rational to use DOACs for VTE treatment among patients with SCD rather than use VKAs. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2020 ◽  
Vol 135 (20) ◽  
pp. 1783-1787 ◽  
Author(s):  
Erica M. Sparkenbaugh ◽  
Chunsheng Chen ◽  
Tomasz Brzoska ◽  
Julia Nguyen ◽  
Shaobin Wang ◽  
...  

Abstract Vaso-occlusive crisis (VOC) is the primary cause of morbidity and hospitalization in sickle cell disease (SCD); however, only 4 therapies (hydroxyurea, l-glutamine, crizanlizumab, and voxeletor) are currently approved in SCD. These agents limit the duration, severity, and frequency of crises. Activation of coagulation is a hallmark of SCD. Studies in animal models of SCD have shown that coagulation contributes to the chronic inflammation and end-organ damage associated with the disease; however, it is unknown whether coagulation directly contributes to the microvascular stasis that causes VOC. Herein, we demonstrate that inhibition of tissue factor (TF) and the downstream coagulation proteases factor Xa and thrombin significantly attenuates heme-induced microvascular stasis in mouse models of VOC. Pharmacologic inhibition of the principal thrombin receptor, protease activated receptor-1 (PAR-1), as well as deficiency of PAR-1 in all nonhematopoietic cells, also reduces stasis in sickle mice. PAR-1 deficiency was associated with reduced endothelial von Willebrand factor expression, which has been shown to mediate microvascular stasis. In addition, TF inhibition reduces lung vaso-occlusion in sickle mice mediated by arteriolar neutrophil-platelet microemboli. In sum, these results suggest that prophylactic anticoagulation might attenuate the incidence of VOC.


1997 ◽  
Vol 100 (2) ◽  
pp. 245-248 ◽  
Author(s):  
D. Helley ◽  
Claude Besmond ◽  
Rolande Ducrocq ◽  
F. da Silva ◽  
Marie-Claude Guillin ◽  
...  

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2272-2272
Author(s):  
Vishal K Gupta ◽  
Romy Carmen Lawrence ◽  
Sarah L. Khan ◽  
Rachel Strykowski ◽  
Brittany Scarpato ◽  
...  

Patients with sickle cell disease (SCD) experience accelerated morbidity and mortality. Venous thromboembolism (VTE), a risk factor for early mortality in SCD, occurs in 11-12% of patients with SCD by the age of 40. While indefinite anticoagulation is indicated in the SCD population, there is limited understanding of comparative efficacy and hemorrhagic risk of individual anticoagulation agents in this population. We reviewed the use of anticoagulation for treatment of VTE in patients with SCD at our institution to begin to address these questions. A retrospective chart review of all patients with SCD 18 years of age and older (currently alive or deceased) who received care at Boston Medical Center/Boston University between 2003 and 2018 was performed. VTE was defined as deep venous thrombosis (DVT) diagnosed by duplex ultrasound or pulmonary embolism (PE) diagnosed by either ventilation-perfusion scanning or computed tomography angiography. The primary efficacy outcome was the number of VTE events which occurred while the patient was receiving anticoagulation. The primary safety outcome was major bleeding as defined by the International Society on Thrombosis and Hemostasis 2005 guidelines. The medical records of 233 patients with SCD were reviewed; VTE was identified in 55 (23.6%) patients. Sixty-five percent were female. In these 55 patients, a total of 94 VTE events occurred. Fifteen (16.0%) were catheter-associated upper extremity DVTs. For the first event, initial outpatient treatment consisted of warfarin in 56%, low-molecular-weight heparin (LMWH) in 18.2%, rivaroxaban in 9.1%, apixaban in 5.5%, and fondaparinux in 3.6%. The median length of treatment was 7.3 (median: 6, IQR: 3-12) months. Recurrent VTEs occurred in 27 (49%) patients with a total of 39 recurrent events. Among the recurrent events, thirteen (33.0%) were treatment failures occurring during anticoagulation therapy (see Table 1): 7 of 37 (18.9%) on warfarin, 2 of 20 (10.0%) on LMWH, and 4 of 15 (26.7%) on rivaroxaban. Death from recurrent VTE occurred in two patients; one occurred while a patient was therapeutic on warfarin. Major bleeding occurred in two patients (3.6%); in both cases, this was intracranial hemorrhage while on warfarin. In this retrospective study, there was a high rate of VTE recurrence despite anticoagulation in patients with SCD. Treatment failure was highest with warfarin and rivaroxaban, although adherence was difficult to assess. Risk of hemorrhage and death appears higher in those prescribed warfarin. These data affirm the need for long-term anticoagulation in most patients with SCD with a VTE and support the use of direct oral anticoagulants as a first-line agent. Disclosures Sloan: Abbvie: Other: Endpoint Review Committee; Stemline: Consultancy; Merck: Other: endpoint review commitee.


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