Thrombosis and haemostasis最新文献

Background:  Thrombin is a multifunctional regulatory enzyme of the haemostasis and has both pro- and anticoagulant roles. It has, therefore, been a main target for drug discovery over many decades. Thrombin is a serine protease and possesses two positively charged regions called exosites, through which it is known to bind to many substrates. Dabigatran is a thrombin inhibitor and is widely used as an oral anticoagulant for the antithrombotic treatment of atrial fibrillation and venous thromboembolism. The mechanism by which dabigatran inhibits thrombin is the blockage of the active site, however, its effect on thrombin binding to its substrates has not been studied thoroughly and is thus poorly understood.

Material and methods:  The effect of dabigatran on thrombin binding to platelets was evaluated by flow cytometry using fluorescently labelled thrombin and washed platelets. Further, to confirm the results we utilized modern techniques for biomolecular binding studies, microscale thermophoresis (MST) and surface plasmon resonance (SPR), which validated the results.

Results:  Dabigatran inhibited thrombin binding to platelets as analysed by flow cytometry. The inhibition was dose dependent with IC50 of 118 nM which was slightly lower than for inhibition of platelet activation and is close to the clinically relevant plasma concentration of dabigatran. MST and SPR also confirmed inhibitory effect of dabigatran on thrombin binding to platelets.

Conclusion:  Apart from blocking the active site, dabigatran also inhibits thrombin binding to platelets. Since thrombin has numerous functions beyond the cardiovascular system, this finding may have important implications.

Background:  In young women with venous thromboembolism (VTE) related to weak transient risk factors, it remains unknown whether stress levels and intimate partner violence (IPV) are associated with recurrence. The VTE-WEAK study aims to investigate the association between perceived stress and IPV with a recurrence of VTE in women with a first episode of VTE due to combined oral contraceptives, pregnancy-puerperium, minor trauma/fracture, brief surgery, infection or brief immobility, and not using antithrombotic prophylaxis.

Material and methods:  We performed a multicenter, international, observational, retrospective study on women referred for thrombophilia screening who were subsequently monitored. Patients were aged 18 to 55 years old and free of high-risk thrombophilia. When a recurrence of VTE was suspected for the first time, the perceived stress level and IPV were evaluated using self-administrated PSS-10 and Woman Abuse Screening Tool (WAST) questionnaires.

Results:  We monitored 7,754 women over 43,880 patients-years. A first suspected recurrence occurred in 4,772 women, among whom 1,316 had an objectively confirmed recurrence. The perceived stress level and an IPV situation were both independent risk factors for recurrence: moderate stress: adjusted odds ratio (aOR) 1.630 (1.415-2.468); high perceived stress: aOR 10.03 (7.528-13.36); IPV: 1.953 (1.546-2.468), p < 0.0001.

Conclusion:  The perceived level of stress and IPV are associated with a recurrence of VTE when suspected. The mechanisms and clinical consequences of a possible stress coagulopathy require investigation.

Objective:  The present work evaluates the predictive value of low-density granulocytes (LDGs) for the development of cardiovascular disease (CVD) and/or bone deterioration (BD) in a 6-year prospective study in systemic lupus erythematosus (SLE). Considering the high SLE-LDG capacity to form neutrophil extracellular traps (NETs), circulating levels of total cell-free DNA (cirDNA) and relative amounts of mitochondrial and nuclear DNA (mtDNA and nDNA, respectively) were tested as LDG-associated biomarkers to identify SLE patients at risk of CVD and BD.

Material and methods:  The frequency of total blood LDGs, as well as the CD16^negCD14^neg (nLDG) and CD16^posCD14^low (pLDG) subsets, was quantified by flow cytometry in 33 controls and 144 SLE patients. Total cirDNA and relative amounts of mitochondrial (mtDNA) and nuclear (nDNA) cell-free DNA were measured by fluorometry or qPCR in plasma from a subgroup of 117 patients and 23 controls at enrolment.

Results and conclusion:  Our findings showed increased blood levels of SLE-nLDGs at enrolment associated with prospective CVD development (pCVD) and the presence of BD, thus revealing LDG expansion as a predictor of both comorbidities in SLE progression. The amounts of the different types of circulating DNA analyzed were increased in patients, especially those presenting with traditional CV risk factors or subclinical atheromatosis. Similar to nLDGs, the nDNA concentration could predict the development of pCVD in SLE, supporting the quantification of cirDNA levels as a surrogate marker of LDGs in clinical practice.

Background:  This study aimed to identify novel plasma proteins associated with first-lifetime venous thromboembolism (VTE) and molecular pathways involved in VTE pathogenesis.

Methods:  A case-cohort comprising incident VTE cases (n = 294) and a randomly sampled age- and sex-weighted subcohort (n = 1,066) was derived from the Trøndelag Health Study (HUNT3, n = 50,800). Blood samples were collected and stored at cohort inclusion (2006-2008), and participants were followed up to 5 years. Proteome-wide analyses was performed using the 7k SomaScan® proteomics platform, and weighted Cox-regression models adjusted for age, sex, and sample batch were conducted, with the Bonferroni method applied to account for multiple testing. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were applied on the top-ranked 200 proteins associated with VTE.

Results:  Out of 7,288 human proteins, 7 proteins were significantly associated with higher VTE risk with p-value <6.9 × 10^-6 (hazard ratios per 1 standard deviation increase in protein levels ranging from 1.39 to 1.86). Except for coagulation factor VIII and tumor necrosis factor soluble receptor II, these proteins were novel associations and included collagen alpha-3(VI):BPTI/Kunitz inhibitor, histo-blood group ABO system transferase, peroxidasin, human epididymis protein 4, and regulator of G protein signaling 3. KEGG analyses of the top-ranked 200 proteins revealed significant pathway enrichment of nine proteins in the complement (mainly lectin pathway) and coagulation (mainly intrinsic pathway) cascades.

Conclusion:  Our proteome-wide analysis led to discovery of five novel protein candidates associated with 5-year risk of future VTE. KEGG analyses supported an interplay between the complement and coagulation pathways in the pathogenesis of VTE.

Background:  Megakaryocytes (MK) from Bernard-Soulier syndrome (BSS) induced pluripotent stem cells (iPSCs) yielded reduced numbers but increased sizes of platelets. The molecular mechanisms remain unclear. This study aims to determine roles of signaling molecules involved in this process.

Material and methods:  Wild-type (WT) iPSCs and iPSCs from BSS patients with GP1BA (BSS-A) or GP1BB (BSS-B) mutations were differentiated into MKs and platelets with or without myosin II inhibitor (blebbistatin), ROCK inhibitor (Y27632), and procaspase-3 activator (PAC-1). Proplatelet and platelet numbers and sizes were characterized. The iPSC lines containing tubulin-green fluorescent protein (GFP) reporters were constructed to observe proplatelet formation under time-lapse microscopy.

Result:  BSS-derived MKs (BSS-MKs) yielded fewer but larger platelets compared with the WT. In the presence of blebbistatin, ROCK inhibitor, or PAC-1, WT, BSS-A, and BSS-B MKs could generate more platelets with decreased sizes, but PAC-1 caused CD42 loss on WT platelets. The proportions of proplatelet formation from MKs carrying tubulin-GFP were not different between WT and BSS-MKs, as well as among inhibitors. Notably, initially thick cytoplasmic processes were transformed into thin branching proplatelets over the observation time. The proplatelet shafts of BSS-MK became thinner in the presence of blebbistatin or ROCK inhibitor, but not of PAC-1, which displayed uneven F-actin distribution.

Conclusion:  Inhibition of the ROCK/myosin pathway, downstream of GpIb, could restore normal morphology of proplatelets in BSS-MKs. Procaspase-3 activation could increase platelet yields, but with abnormal proplatelet and platelet structures. Our model can be used for therapeutic drug screening and a disease model for platelet production in the future.

Background and Purpose This study aimed to explore the relationship between lipidomic domains, particularly free fatty acids (FFAs), and the presence of AF in patients with acute stroke, and to identify mechanisms of AF-associated stroke through genetic studies. Methods A total of 483 patients of stroke in patients without AF (n = 391) and with AF (n = 92) were selected from a prospectively collected stroke registry. Lipidomic profiling was conducted and the lipid components associated with AF were explored using fold-change analyses and clustering. Genotyping was conducted through trait comparison. Colocalization was also performed. Results Among the lipidomic domains, the free fatty acid (FFA) class was positively associated with AF. Long-chain fatty acids with 14-24 carbons and unsaturated FFAs distinguished AF. Clustering analysis based on FFAs revealed differences in AF proportion across groups. GWAS identified two loci associated with clustered groups of FFA metabolites: near MIR548F3 associated with FFA 20:1, FFA 20:2, FFA 22:5, and FFA 22:6; and near RPL37A associated with FFA 22:5 and FFA 22:6. These loci were associated with increased fibrinogen levels. In the GWAS for the FFA metabolite-quantitative trial locus analysis, loci near rs28456 and rs3770088, and FFA 20:4-QTLs were co-localized with the eQTLs of FADS2, a gene involved in the peroxisome proliferative-activated receptor gamma-related signaling pathway, in the whole blood, left ventricle, and atrial appendage tissue. Conclusion Elevated FFA levels, especially those of long-chain unsaturated FFAs, are strongly associated with AF-associated stroke. This relationship is regulated by the peroxisome proliferator-activated receptor gamma-related signaling pathway.

Bleeding complications associated with oral anticoagulant (OAC) frequently lead to emergency department visits and hospitalization. Short-term all-cause mortality after severe bleeding is substantial ranging from approximately 10% for gastrointestinal bleeding (the most frequent single site) to approximately 50% for intracranial bleeding. A protocol for multidisciplinary approach to bleeding is needed to (i) ensure rapid identification of patients at risk of adverse outcomes, (ii) optimize delivery of supportive measures, (iii) treat the source of bleeding, and (iv) administer anticoagulant reversal or hemostatic therapies judiciously for patients most likely to benefit. We convened a multidisciplinary panel of experts (emergency medicine, gastroenterology, general internal medicine, hematology, neurology, pharmacy, thrombosis) to review the literature and provide practical guidance including a corresponding algorithm for use at the point of care to assist clinicians in the management of patients with acute severe OAC-related bleeding.

Background:  Hypertension is a well-known risk factor for atrial fibrillation (AF) and strokes, but studies assessing screening-detected AF in hypertensive populations and its relationship to the blood pressure (BP) are scarce.

Method:  We prospectively recruited hypertensive patients (aged ≥60 years) from all over Japan in a decentralized clinical trial. Participants were asked to measure their electrocardiogram (ECG) and BP at home for 3 months with a BP monitor equipped with ECG.

Results:  Between April 2022 and July 2023, 4,078 hypertensive patients from across the country participated in this study. The mean age was 66.3 ± 5.5 years, and the male proportion was 80.3%. After excluding those with no measurement data (n = 258), AF detection was 5.8% (n = 220/3,820), and the time to AF detection was 3 to 109 days (median 28 days). The mean BP at baseline was 133 ± 14/85 ± 9 mmHg in the morning and 125 ± 14/79 ± 9 mmHg in the evening. AF detection did not significantly differ between the baseline BP categories (log rank test, p = 0.54), with hazard ratios (95% confidence interval) of 0.83 (0.57-1.19), 0.79 (0.55-1.14), and 0.99 (0.59-1.68) for systolic BP (SBP) 135 to 144 and/or diastolic BP (DBP) 85 to 89, SBP 145 to 159 and/or DBP 90 to 99, and SBP ≥ 160 and/or DBP ≥ 100, respectively (SBP ≤ 134 and DBP ≤ 84 as a reference). The results did not change when taking into account the impact of the measurement rates and antihypertensive drugs on AF detection during the observation period.

Conclusion:  Detection of undiagnosed AF was 5.8% in elderly hypertensives, with no significant differences between the baseline BP categories and no effect of the measurement rate or antihypertensive drugs.

Background:  Portal vein system thrombosis (PVST) is a frequent and possibly fatal concurrent disorder following splenectomy. The optimal anticoagulant to prevent PVST following splenectomy remains unclear.

Objectives:  The purpose of this study was to compare the safety and efficacy of apixaban versus aspirin in preventing PVST after laparoscopic splenectomy (LS) for cirrhotic hypersplenism.

Methods:  In this single-center randomized controlled trial, 80 patients with liver cirrhosis who received LS were randomly allocated to two treatment arms that were treated with apixaban or aspirin for 6 months. The primary effectiveness outcome was PVST formation after LS.

Results:  We excluded four patients who withdrew from the study. The dynamic incidence of PVST, main and intrahepatic branches of PVST, and splenic vein thrombosis in the 6 postoperative months were all significantly lower in the apixaban treatment arm compared to the aspirin treatment arm (all P <0.001). Significantly lower incidences of PVST, main and intrahepatic branches of PVST, and splenic vein thrombosis in apixaban treatment arm started from postoperative day 7, month 1, and day 7 compared to the aspirin treatment arm respectively (all P <0.05). Multiple logistic regression analysis revealed that apixaban was an independent protective factor for PVST at postoperative month 3, as compared with aspirin (relative risk, 0.057; 95% confidence interval, 0.013-0.248; P <0.001).

Conclusion:  Compared with aspirin, apixaban could earlier and more effectively prevent PVST following LS for cirrhotic hypersplenism. Apixaban can be chosen as a priority treatment option versus aspirin, contributing to a lower risk of PVST.

Aim To assess an optimal long-term antiplatelet strategy in patients at both high ischaemic and bleeding risks after percutaneous coronary intervention (PCI). Methods and results Patients both at high ischaemic and bleeding risks were eligible for inclusion. We excluded patients with any ischaemic and major bleeding complications during the mandatory period of dual antiplatelet therapy (DAPT). Clinical outcomes were evaluated in three groups of regimen, in terms of, clopidogrel monotherapy (CLPD), aspirin monotherapy (ASA) and DAPT group. The primary endpoint was a composite of all-cause death, myocardial infarction, stroke or major bleeding for 12-month follow-up period. To balance characteristics according to antiplatelet strategies, stabilized inverse probability treatment weighting (IPTW) was conducted. After IPTW adjustment, CLPD group (N=916) showed the significantly lower rate of primary endpoint than DAPT group (N=949) (Hazard Ratio [HR]=2.09, 95% confidence interval (CI)= 1.22 - 3.60, p=0.008], but there was no statistical difference between CLPD and ASA (N=838) groups (HR=1.46, 95% CI=0.83-2.54, p=0.187). Clinical benefits of CLPD over DAPT was mainly driven by the lower incidence of ischaemic events (HR = 2.51, 95% CI 1.37-4.61; p = 0.003). Incidence of major bleeding did not differ among groups, but there was an increased bleeding tendency in DAPT group compared to CLPD group (HR=2.51, 95% CI=0.85-7.41, p=0.096). Conclusion For patients at high bleeding and ischaemic risk especially undergoing complex PCI, clopidogrel monotherapy demonstrated a significant net clinical benefit compared to DAPT. Clopidogrel monotherapy showed numerical reductions of bleeding and ischaemic event rates compared to aspirin monotherapy.