Thrombosis and haemostasis最新文献

Background:  Platelet C-type lectin-like receptor 2 (CLEC-2) induces platelet activation and aggregation after clustering by its ligand podoplanin (PDPN). PDPN, which is not normally expressed in cells in contact with blood flow, is induced in inflammatory immune cells and some malignant tumor cells, thereby increasing the risk of venous thromboembolism (VTE) and tumor metastasis. Therefore, small-molecule compounds that can interfere with the PDPN-CLEC-2 axis have the potential to become selective antiplatelet agents.

Methods and results:  Using molecular docking analysis of CLEC-2 and a PDPN-CLEC-2 binding-inhibition assay, we identified a group of diphenyl-tetrazol-propanamide derivatives as novel CLEC-2 inhibitors. A total of 12 hit compounds also inhibited PDPN-induced platelet aggregation in humans and mice. Unexpectedly, these compounds also fit the collagen-binding pocket of the glycoprotein VI molecule, thereby inhibiting collagen interaction. These compounds also inhibited collagen-induced platelet aggregation, and one compound ameliorated collagen-induced thrombocytopenia in mice. For clinical use, these compounds will require a degree of chemical modification to decrease albumin binding.

Conclusion:  Nonetheless, as dual activation of platelets by collagen and PDPN-positive cells is expected to occur after the rupture of atherosclerotic plaques, these dual antagonists could represent a promising pharmacophore, particularly for arterial thrombosis, in addition to VTE and metastasis.

Background:  The Caprini risk assessment model (RAM) is the most commonly used tool for evaluating venous thromboembolism (VTE) risk, a high score for arthroplasty can result in patients being classified as high risk for VTE. Therefore, its value in post-arthroplasty has been subject to debate.

Methods:  Retrospective data were collected from patients who underwent arthroplasty between August 2015 and December 2021. The study cohort included 3,807 patients, all of whom underwent a thorough evaluation using Caprini RAM and vascular Doppler ultrasonography preoperatively.

Results:  A total of 432 individuals (11.35%) developed VTE, while 3,375 did not. Furthermore, 32 (0.84%) presented with symptomatic VTE, while 400 (10.51%) were detected as asymptomatic. Additionally, 368 (9.67%) VTE events occurred during the hospitalization period, and 64 (1.68%) cases were detected during postdischarge follow-up. Statistical analysis revealed significant differences between the VTE and non-VTE groups in terms of ages, blood loss, D-dimer, body mass index >25, visible varicose veins, swollen legs, smoking, history of blood clots, broken hip, percent of female, hypertension, and knee joint arthroplasty (p < 0.05). The Caprini score was found to be significantly higher in the VTE group (10.10 ± 2.23) compared with the non-VTE group (9.35 ± 2.14) (p < 0.001). Furthermore, there was a significant correlation between the incidence of VTE and the Caprini score (r = 0.775, p = 0.003). Patients with a score ≥9 are at a high-risk threshold for postoperative VTE.

Conclusion:  The Caprini RAM shows a significant correlation with the occurrence of VTE. A higher score indicates a greater likelihood of developing VTE. The score ≥9 is at particularly high risk of developing VTE.

Background:  Dementia and atrial fibrillation (AF) have many shared risk factors. Besides, patients with dementia are under-represented in randomized trials, and even if AF is present, oral anticoagulants (OACs) are not prescribed frequently. This study aimed to report the incidence of newly diagnosed AF in dementia patients, and the impacts of use of vitamin K antagonist (VKA; e.g., warfarin) and non-VKA OAC (NOACs) on stroke and bleeding outcomes.

Methods:  Our study utilized the Taiwan National Health Insurance Research Database. A total of 554,074 patients with dementia were compared with 554,074 age- and sex-matched patients without dementia regarding the risk of incident AF. Among patients with dementia who experienced incident AF, the risks of clinical events of patients treated with warfarin or NOACs were compared with those without OACs (reference group).

Results:  The risk of incident AF was greater for patients with dementia compared with those without (adjusted hazard ratio [aHR]: 1.054; 95% confidence interval [CI]: 1.040-1.068 for all types of dementia, aHR: 1.035; 95% CI: 1.020-1.051 for presenile/senile dementia, and aHR: 1.125; 95% CI: 1.091-1.159 for vascular dementia). Among patients with dementia and experienced incident AF, warfarin use was associated with a higher risk of ischemic stroke (aHR: 1.290; 95% CI: 1.156-1.440), intracranial hemorrhage (ICH; aHR: 1.678; 95% CI: 1.346-2.090), and major bleeding (aHR: 1.192; 95% CI: 1.073-1.323) compared with non-OACs. NOAC use was associated with a lower risk of ischemic stroke (aHR: 0.421; 95% CI: 0.352-0.503) and composite risk of ischemic stroke or major bleeding (aHR: 0.544; 95% CI: 0.487-0.608) compared with non-OACs. These results were consistent among the patients after the propensity matching.

Conclusion:  In this large nationwide cohort, the risk of newly diagnosed AF was higher in patients with dementia (all dementia, presenile/senile dementia, and vascular dementia) compared with those without dementia. For patients with dementia who experienced incident AF, NOAC use was associated with a better clinical outcome compared with non-OAC. Patients with dementia require a holistic approach to their care and management, including the use of NOACs to reduce the risks of clinical events.

Background:  Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). MicroRNAs (miRs) may influence platelet function and maturity, and subsequently the effect of antiplatelet therapy.

Objectives:  We aimed to explore the association between miR expression and platelet function and maturity in patients with acute STEMI and healthy individuals.

Methods:  We performed an observational study of STEMI patients admitted directly to primary percutaneous coronary intervention. Patients were treated with antiplatelet therapy according to guidelines. Within 24 hours after admission, blood samples were obtained to measure: the expression of 10 candidate miRs, platelet function markers using advanced flow cytometry, platelet aggregation, serum thromboxane B₂, and platelet maturity markers. Furthermore, blood samples from healthy individuals were obtained to determine the normal variation.

Results:  In total, 61 STEMI patients and 50 healthy individuals were included. STEMI patients had higher expression of miR-21-5p, miR-26b-5p, and miR-223-3p and lower expression of miR-150-5p, miR423-5p, and miR-1180-3p than healthy individuals. In STEMI patients, the expression of miR-26b-5p showed the most consistent association with platelet function (all p-values <0.05, Spearman's rho ranging from 0.27 to 0.41), while the expression of miR-150-5p and miR-223-3p showed negative associations with platelet function. No association between miR expression and platelet maturity markers was observed.

Conclusion:  In patients with STEMI, the expression of six miRs was significantly different from healthy individuals. The expression of miR-26b-5p may affect platelet function in acute STEMI patients and potentially influence the effect of antiplatelet therapy.

Background:  Given the current debate in clinical research about the relationship between tobacco smoking and the risk of venous thromboembolism (VTE), a Mendelian randomization (MR) study was conducted aimed at elucidating the causal associations of current and past tobacco smoking with the risk of VTE, from the perspective of genetics.

Methods:  Two-sample univariate and multivariable MR analyses were designed, using summary-level data from large genome-wide association studies involving European individuals. Causality was primarily assessed using multiplicative fixed-effects or random-effects model and inverse variance weighting, supplemented by MR-Egger regression, MR-PRESSO, Cochran's Q test, and leave-one-out for sensitivity analysis to test the reliability of the results.

Results:  In the univariate MR analysis, no significant causal effects were found between current tobacco smoking and the risk of VTE, deep vein thrombosis (DVT), and pulmonary embolism (PE). Similarly, no significant causal effects were found between past smoking and VTE, DVT, and PE. As for the multivariable MR analysis, results were consistent with univariate MR analysis, with no significant causal effect of either current or past tobacco smoking on the risk of VTE, DVT, and PE.

Conclusion:  Evidence from both univariate and multivariable MR analyses demonstrated no significant causal relationships between current and past tobacco smoking and VTE, DVT, and PE. This contradicts positive correlations reported in some previous observational studies, which may be explained by other confounding factors. This provided genetic evidence for the conclusion reported in other observational studies that smoking did not affect VTE risk.

Background:  Vascular injury results in uncontrollable hemorrhage in hemorrhagic diseases and excessive antithrombotic therapy. Safe and efficient hemostatic agents which can be orally administered are urgently needed. Platelets play indispensable roles in hemostasis, but there is no drug exerting hemostatic effects through enhancing platelet function.

Methods:  The regulatory effects of icaritin, a natural compound isolated from Herba Epimedii, on the dense granule release, thromboxane A₂ (TxA₂) synthesis, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by multiple agonists were investigated. The effects of icaritin on tail vein bleeding times of warfarin-treated mice were also evaluated. Furthermore, we investigated the underlying mechanisms by which icaritin exerted its pharmacological effects.

Results:  Icaritin alone did not activate platelets, but significantly potentiated the dense granule release, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by thrombin and U46619. Icaritin also shortened tail vein bleeding times of mice treated with warfarin. In addition, phosphorylated proteome analysis, immunoblotting analysis, and pharmacological research revealed that icaritin sensitized the activation of phospholipase Cγ2 (PLCγ2)-protein kinase C (PKC) signaling pathways, which play important roles in platelet activation.

Conclusion:  Icaritin can sensitize platelet activation induced by thrombin and TxA₂ through enhancing the activation of PLCγ2-PKC signaling pathways and promote hemostasis, and has potential to be developed into a novel orally deliverable therapeutic agent for hemorrhages.