Platelet Thrombus Research Articles

Xylitol is prothrombotic and associated with cardiovascular risk.

The pathways and metabolites that contribute to residual cardiovascular disease risks are unclear. Low-calorie sweeteners are widely used sugar substitutes in processed foods with presumed health benefits. Many low-calorie sweeteners are sugar alcohols that also are produced endogenously, albeit at levels over 1000-fold lower than observed following consumption as a sugar substitute. Untargeted metabolomics studies were performed on overnight fasting plasma samples in a discovery cohort (n = 1157) of sequential stable subjects undergoing elective diagnostic cardiac evaluations; subsequent stable isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses were performed on an independent, non-overlapping validation cohort (n = 2149). Complementary isolated human platelet, platelet-rich plasma, whole blood, and animal model studies examined the effect of xylitol on platelet responsiveness and thrombus formation in vivo. Finally, an intervention study was performed to assess the effects of xylitol consumption on platelet function in healthy volunteers (n = 10). In initial untargeted metabolomics studies (discovery cohort), circulating levels of a polyol tentatively assigned as xylitol were associated with incident (3-year) major adverse cardiovascular event (MACE) risk. Subsequent stable isotope dilution LC-MS/MS analyses (validation cohort) specific for xylitol (and not its structural isomers) confirmed its association with incident MACE risk [third vs. first tertile adjusted hazard ratio (95% confidence interval), 1.57 (1.12-2.21), P < .01]. Complementary mechanistic studies showed xylitol-enhanced multiple indices of platelet reactivity and in vivo thrombosis formation at levels observed in fasting plasma. In interventional studies, consumption of a xylitol-sweetened drink markedly raised plasma levels and enhanced multiple functional measures of platelet responsiveness in all subjects. Xylitol is associated with incident MACE risk. Moreover, xylitol both enhanced platelet reactivity and thrombosis potential in vivo. Further studies examining the cardiovascular safety of xylitol are warranted.

Pilot Assessment of Platelet Thrombus Area and Contractile Force in Pediatric Congenital Heart Surgery Patients Using a Microfluidic Device

ObjectivesEvaluate maximum platelet contractile force and thrombus area before and after cardiopulmonary bypass (CPB) in pediatric patients having congenital heart disease (CHD) surgery using a microfluidic device. DesignProspective cohort study. SettingAcademic medical center. ParticipantsTwenty pediatric CHD patients ≤ 8 years of age with expected CPB time >30 minutes. InterventionsNone Measurements and Main ResultsBlood was collected at baseline and post-CPB. Maximum platelet contractile force and thrombus area were evaluated in vitro using a microfluidic device (ATLAS PST). Post-CPB samples were supplemented with recombinant von Willebrand Factor (rVWF) to explore impact on contractile force and thrombus area. At baseline, maximum thrombus area was 0.06 [0.05, 0.07] and maximum force was 123.3 nN [68.4, 299.5]. Linear mixed effects regression models showed that maximum thrombus area was larger post-CPB and post-CPB + rVWF compared to pre-CPB (Est=0.04, p=0.002 and Est = 0.09, p < .001, respectively). Maximum thrombus area was also larger post-CPB + rVWF compared to post-CPB (Est=0.04, p=0.001). Force was higher post-CPB + rVWF compared to pre-CPB (Est=173.32, p=0.044). ConclusionsIn pediatric CHD patients, microfluidic testing demonstrated that platelet thrombus area increased slightly after CPB, while platelet contractile force did not change. In vitro addition of rVWF further increased thrombus area, suggesting augmentation of primary hemostasis. Microfluidic assessment of platelet contractile force and thrombus area in pediatric CHD patients appears feasible and can demonstrate changes after CPB. Further studies are needed to determine its accuracy and clinical utility, as well as normal values for pediatric patients.

Optimizing inferior vena cava filter design: A computational fluid dynamics study on strut configuration for enhanced hemodynamic performance and thrombosis reduction

Background and objectiveInferior vena cava filters have been shown to be effective in preventing deep vein thrombosis and its secondary complication, pulmonary embolism, thereby reducing the high mortality rate. Although inferior vena cava filters have evolved, specific complications like inferior vena cava thrombosis-induced deep vein thrombosis worsening and recurrent pulmonary embolism continue to pose challenges. This study analyzes the effects of geometric parameter variations of inferior vena cava filters, which have a significant impact on the thrombus formation inside the filter, the capture, dissolution, and hemodynamic flow of thrombus, as well as the shear stress on the filter and vascular wall. MethodsThis study used computational fluid dynamic simulations with the carreau model to investigate the impact of varying inferior vena cava filter design parameters (number of struts, strut arm length, and tilt angle) on hemodynamics. ResultsRecirculation and stagnation areas due to flow velocity and pressure, along with wall shear stress values, were identified as key factors. It is important to find a balance between wall shear stress high enough to aid thrombolysis and low enough to prevent platelet activation. The results of this paper show that the risk of platelet activation and thrombus filtration may be lowest when the wall shear stress of the filter ranges from 0 to 4 [Pa], minimizing stress concentration within the filter. Conclusion16 arm struts with a length of 20 mm and a tilt angle of 0° provide the best balance between thrombus capture and minimization of hemodynamic disturbance. This configuration minimizes the size of the stagnation and recirculation zones while maintaining sufficient wall shear stress for thrombus dissolution.

#2699 Rare glomerular microangiopathy: clinicopathological characteristics and prognosis

Abstract Background and Aims Different from the typical histologic changes of thrombotic microangiopathy (TMA), we identified a group of patients whose pathology with glomerular involvement without blood vessel lesions, which was rare and known as glomerular microangiopathy (GMA). Method In Peking Union Medical College Hospital, a total of 33 patients were diagnosed as GMA with proliferation and swelling of glomerular endothelial cells, fragmented red blood cells, fibrin or platelet thrombi in the capillary lumen, thickening of the basement membrane, stenosis or occlusion of capillary lumen, but no abnormalities in the endothelium of renal small vessels. The pathology and clinical data were from the medical records and analyzed. Results The patients were 66.7% male with a mean of 45 years (14 to 74 years). The primary diseases were Castleman's disease (CD, 30.3%), POEMS syndrome (21.2%), cancer patients receiving agents targeting vascular endothelial growth factor (21.2%), and others. All the patients showed various degrees of proteinuria, with an average 24-hour urinary protein of 2.66 g/d, hematuria (63.6%), and acute kidney injury (AKI, 39.4%). The median serum creatinine (SCr) was 142 (107.5, 169) μmol/L. The AKI patients had lower Alb (P &amp;lt; 0.0001), PLT (P = 0.0192), higher high-sensitivity C-reactive protein (hs-CRP) (P = 0.0199), and reduction of IgA (P = 0.0021). There is no significant difference in SCr and proteinuria among patients with different etiologies. The CD patients exhibited higher hs-CRP and D-Dimer. Treatment included targeting therapy of underlying hematological disorders, glucocorticoid combination with or without immunosuppressant, and supportive treatment. After treatment, we observed proteinuria remission (66.7%), partial improvement (27.3%), or complete recovery (45.5%) of renal function. Conclusion In Castleman's disease, POEMS syndrome, and patients receiving agents targeting VEGF, initial attention to GMA might improve the prognosis and shed light on the study of the mechanisms.

Essential role of glycoprotein Ibα in platelet activation

AbstractGlycoprotein Ibα (GPIbα), the ligand-binding subunit of platelet GPIb-IX complex, interacts with von Willebrand factor (VWF) exposed at the injured vessel wall, initiating platelet adhesion, activation, hemostasis, and thrombus formation. The cytoplasmic tail of GPIbα interacts with 14-3-3ζ, regulating the VWF-GPIbα–elicited signal transduction and VWF binding function of GPIbα. However, we unexpectedly found that the GPIbα–14-3-3ζ association, beyond VWF-dependent function, is essential for general platelet activation. We found that the myristoylated peptide of GPIbα C-terminus MPαC, a potential GPIbα inhibitor, by itself induced platelet aggregation, integrin αIIbβ3 activation, granule secretion, and phosphatidylserine (PS) exposure. Conversely, the deletion of the cytoplasmic tail of GPIbα in mouse platelets (10aa−/−) decreased platelet aggregation, integrin αIIbβ3 activation, granule secretion, and PS exposure induced by various physiological agonists. Phosphoproteome-based kinase activity profiling revealed significantly upregulated protein kinase C (PKC) activity in MPαC-treated platelets. MPαC-induced platelet activation was abolished by the pan-PKC inhibitor and PKCα deletion. Decreased PKC activity was observed in both resting and agonist-stimulated 10aa−/− platelets. GPIbα regulates PKCα activity by sequestering 14-3-3ζ from PKCα. In vivo, the deletion of the GPIbα cytoplasmic tail impaired mouse hemostasis and thrombus formation and protected against platelet-dependent pulmonary thromboembolism. Therefore, our findings demonstrate an essential role for the GPIbα cytoplasmic tail in regulating platelet general activation and thrombus formation beyond the VWF–GPIbα axis.

Regulation of platelet activation and thrombus formation in acute non-ST segment elevation myocardial infarction: Role of Beclin1.

This study aims to investigate the mechanism of platelet activation-induced thrombosis in patients with acute non-ST segment elevation myocardial infarction (NSTEMI) by detecting the expression of autophagy-associated proteins in platelets of patients with NSTEMI. A prospective study was conducted on 121 patients with NSTEMI who underwent emergency coronary angiography and optical coherence tomography. The participants were divided into two groups: the ST segment un-offset group (n = 64) and the ST segment depression group (n = 57). We selected a control group of 60 patients without AMI during the same period. The levels of autophagy-associated proteins and the expression of autophagy-associated proteins in platelets were measured using immunofluorescence staining and Western blot. In NSTEMI, the prevalence of red thrombus was higher in the ST segment un-offset myocardial infarction (STUMI) group, whereas white thrombus was more common in the ST segment depression myocardial infarction (STDMI) group. Furthermore, the platelet aggregation rate was significantly higher in the white thrombus group compared with the red thrombus group. Compared with the control group, the autophagy-related protein expression decreased, and the expression of αIIbβ3 increased in NSTEMI. The overexpression of Beclin1 could activate platelet autophagy and inhibit the expression of αIIbβ3. The results suggested that the increase in platelet aggregation rate in patients with NSTEMI may be potentially related to the change in autophagy. And the overexpression of Beclin1 could reduce the platelet aggregation rate by activating platelet autophagy. Our findings demonstrated that Beclin1 could be a potential therapeutic target for inhibiting platelet aggregation in NSTEMI.

Extracellular histones: a unifying mechanism driving platelet-dependent extracellular vesicle release and thrombus formation in COVID-19

BackgroundCOVID-19 can cause profound inflammation and coagulopathy, and while many mechanisms have been proposed, there is no known common pathway leading to a prothrombotic state. ObjectivesFrom the beginning of the COVID-19 pandemic, elevated levels of extracellular histones have been found in plasma of patients infected with SARS-CoV-2. We hypothesized that platelet activation triggered by extracellular histones might represent a unifying mechanism leading to increased thrombin generation and thrombosis. MethodsWe utilized blood samples collected from an early clinical trial of hospitalized COVID-19 patients (NCT04360824) and recruited healthy subjects as controls. Using plasma samples, we measured the procoagulant and prothrombotic potential of circulating extracellular histones and extracellular vesicles (EVs). Platelet prothrombotic activity was assessed via thrombin generation potential and platelet thrombus growth. Circulating EVs were assessed for thrombin generation potential in vitro in plasma and enhancement of thrombotic susceptibility in vivo in mice. ResultsCompared with controls, COVID-19 patients had elevated plasma levels of citrullinated histone H3, cell-free DNA, nucleosomes, and EVs. Plasma from COVID-19 patients promoted platelet activation, platelet-dependent thrombin generation, thrombus growth under venous shear stress, and release of platelet-derived EVs. These prothrombotic effects of COVID-19 plasma were inhibited by an RNA aptamer that neutralizes both free and DNA-bound histones. EVs isolated from COVID-19 plasma enhanced thrombin generation in vitro and potentiated venous thrombosis in mice in vivo. ConclusionWe conclude that extracellular histones and procoagulant EVs drive the prothrombotic state in COVID-19 and that histone-targeted therapy may prove beneficial.

Abstract 138: Platelet RIPK1 Promotes Platelet Activation And Aggregation In Arteriolar Thrombosis And Ischemic Stroke

Receptor-interacting protein Ser/Thr kinase 1 (RIPK1) is a molecular switch for inflammation and cell death in nucleated cells, and its function is controlled by phosphorylation at the Ser166 residue. However, it is unknown whether RIPK1 regulates platelet function in arterial thrombosis. Intravital microscopy using megakaryocyte-specific Ripk1 conditional knockout (CKO) mice ( Ripk1 fl/fl;Pf4-cre ) revealed that platelet Ripk1 promoted platelet thrombus formation at sites of laser-induced cremaster arteriolar thrombosis. Deletion of platelet Ripk1 prolonged the time to occlusion in FeCl 3 -induced carotid arterial thrombosis without affecting tail bleeding times. Further, compared to wild-type (WT) mice, Ripk1 CKO mice exhibited improved neurological deficits and reduced infarct volume in ischemic stroke induced by transient middle cerebral artery occlusion. Flow cytometry and aggregation assays showed that deletion of platelet Ripk1 reduced P-selectin exposure, αIIbβ3 integrin activation, and platelet aggregation induced by thrombin, collagen-related peptides (CRP), and U46619, but not ADP. Pretreatment of Ripk1-null platelets with ADP rescued the aggregation defect. Treatment of platelets with Nec-1s, a RIPK1 inhibitor that blocks RIPK1-Ser166 phosphorylation, did not affect platelet activation and aggregation. Instead, RIPK1-Ser320/321 was rapidly phosphorylated in thrombin- or CRP-stimulated human and mouse platelets. Treatment of platelets with an inhibitor of phospholipase C, p38, or MAPK-activated protein kinase 2 (MK2), but not a protein kinase C inhibitor, decreased RIPK1-Ser320/321 phosphorylation after thrombin or CRP stimulation, implying that the p38-MK2 axis phosphorylates RIPK1-Ser320/321. Using a genetic approach in human megakaryoblastic MEG-01 cells, we found that RIPK1 knockdown reduced granule secretion from stimulated MEG-01 cells, which was rescued by overexpressing WT RIPK1, but not mutant RIPK1-Ser320Ala, in the RIPK1 knockdown MEG-01 cells. These results suggest that platelet RIPK1 enhances granule secretion during platelet activation through p38-MK2-mediated phosphorylation of RIPK1-Ser320/321, thereby contributing to the pathology of thrombotic disease.

Abstract 119: LRRC8 Complex Is An ATP Release Channel Regulating Platelet Activation And Thrombosis

Platelet shape and volume changes are early mechanical events in platelet activation proposed to contribute to arterial thrombosis. Here, we identify single-nucleotide polymorphisms (SNPs) in four leucine-rich repeat containing protein subunits (LRRC8A, B, C, and D) expressed in human platelets that are independently associated with increased mean platelet volume in human genetic studies - implicating the volume-sensing LRRC8 channel complex as regulating platelet function in humans. We show LRRC8A is required for functional LRRC8/VRAC in megakaryocytes (MKs). MK-specific LRRC8A conditional knockout mice give rise to LRRC8A-null platelets with larger mean volumes. LRRC8A-null platelets and CRISPR-edited human LRRC8A KO MKs (hiPSC MKs) have reduced agonist -stimulated P-selectin exposure, and αIIbβ3 integrin activation. LRRC8A-null platelets exhibit impaired adhesion to collagen-coated surfaces, agonist-induced platelet aggregation and ATP secretion. MK-specific LRRC8A conditional knockout mice have reduced platelet thrombus formation in laser-induced cremaster arteriolar thrombosis and prolonged occlusion times in FeCl 3 -induced carotid arterial thrombosis, compared to control mice, without affecting tail bleeding times. Mechanistically, LRRC8A mediates swelling-induced ATP release to amplify agonist-stimulated calcium influx and aggregation in platelets. Treatment of platelets with small-molecule LRRC8 channel inhibitors recapitulate the defects in LRRC8A-null platelets. These studies identify the mechanoresponsive LRRC8 channel complex as a regulator of platelet function and thrombosis - providing a proof-of-concept for a novel anti-thrombotic drug target.

Enhanced coagulation cascade activation and styptic effects of Zn@SiO2 nanocomposite

Humans often have bleeding, which exerts substantial selective pressure on the coagulation system to optimize hemostasis in a variety of situations. Uncontrolled hemorrhage due to severe trauma leads to morbidity and mortality. Although nonbiological surfaces such as silicates can activate coagulation factor XII (FXII), the presence of Zn (Zinc) in the material stimulates and activates the various steps in the coagulation cascade. This results in blood clotting. The Zn@SiO2 nanocomposite has an excellent hemostatic property that establishes hemostasis by activating the factors responsible for the formation of a stable clot called fibrin mesh. This can be used as a hemostatic agent during surgeries and in any other trauma condition related to bleeding. Zn@SiO2 was synthesized and characterized with XRD, FTIR and HRTEM. It is analyzed for its RBC (Red Blood Corpuscles) aggregation and Platelet adhesion ability, fibrin formation, thrombus formation and prothrombin time (PT), Activated Partial Thromboplastin Time (aPTT), D-dimer for its ability to activate the coagulation cascade to achieve stable clotting.

Lipoxin A4 analogue, BML-111, reduces platelet activation and protects from thrombosis

Formyl peptide receptors (FPRs) are members of seven transmembrane G protein-coupled receptors superfamily that exhibit different responses based on the nature of stimulating ligand type. FPRs have been shown to be present in platelets and regulate their function. However, the effect of formyl peptide receptor 2 (FPR2/ALX) lipid ligands on platelets has not yet been addressed. Hence, we sought to study the role of FPR2/ALX ligand and lipoxin A4 lipid analogue, BML-111, in the modulation of platelet function and thrombus formation. Immunofluorescence microscopy showed subcellular distribution and peripheral mobilisation of FPR2/ALX in stimulated platelets. This variation in distribution was further confirmed using flow cytometry. BML-111 inhibited a range of platelet activities in a dose-dependent manner in response to several platelet agonists. This included aggregation, fibrinogen binding to integrin αIIbβ3, α-granule secretion, dense granule secretion, Ca2 + mobilisation and integrin αIIbβ3-mediated outside-in signaling. The selectivity of BML-111 for FPR2/ALX was confirmed using FPR2/ALX deficient mice in flow cytometry assays. In vitro thrombus formation was also inhibited by various concentrations of BML-111. Moreover, the levels of vasodilator stimulated phosphorylation (VASP-S157) increased significantly after BML-111 treatment in resting and stimulated platelets via protein kinase A (PKA) independently of cyclic adenosine monophosphate (cAMP) signaling. Together, our findings demonstrate the significance of BML-111 as a modulator of platelet function via FPR2/ALX and unravel the thrombo-protective potentials of BML-111 induced signaling against thrombo-inflammatory diseases.

In vivo assessment of dual-function submicron textured nitric oxide releasing catheters in a 7-day rabbit model

Catheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. Herein, a dualfunction submicron textured nitric oxide (NO)-releasing catheter was developed. The hemocompatibility and antithrombotic activity of vascular catheters were evaluated in both 20 h in vitro blood loop and 7 d in vivo rabbit model. Surface characterization assessments via atomic force microscopy show the durability of the submicron pattern after incorporation of NO donor S-nitroso-N-acetylpenicillamine (SNAP). The SNAP-doped catheters exhibited prolonged and controlled NO release mimicking the levels released by endothelium. Fabricated catheters showed cytocompatibility when evaluated against BJ human fibroblast cell lines. After 20h in vitro evaluation of catheters in a blood loop, textured-NO catheters exhibited a 13-times reduction in surface thrombus formation compared to the control catheters, which had 83% of the total area covered by clots. After the 7 d in vivo rabbit model, analysis on the catheter surface was examined via scanning electron microscopy, where significant reduction of platelet adhesion, fibrin mesh, and thrombi can be observed on the NO-releasing textured surfaces. Moreover, compared to relative controls, a 63% reduction in the degree of thrombus formation within the jugular vein was observed. Decreased levels of fibrotic tissue decomposition on the jugular vein and reduced platelet adhesion and thrombus formation on the texture of the NO-releasing catheter surface are indications of mitigated foreign body response. This study demonstrated a biocompatible and robust dual-functioning textured NO PU catheter in limiting fouling-induced complications for longer-term blood-contacting device applications. Statement of significanceCatheter-induced thrombosis is a major contributor to infectious and mechanical complications of biomaterials that lead to device failure. This study demonstrated a robust, biocompatible, dual-functioning textured nitric oxide (NO) polyurethane catheter in limiting fouling-induced complications for longer-term blood-contacting device applications.The fabricated catheters exhibited prolonged and controlled NO release that mimics endothelium levels. After the 7 d in vivo model, a significant reduction in platelet adhesion, fibrin mesh, and thrombi was observed on the NO-releasing textured catheters, along with decreased levels of fibrotic tissue decomposition on the jugular vein. Results illustrate that NO-textured catheter surface mitigates foreign body response.

The bile acid receptor TGR5 inhibits platelet activation and thrombus formation

Liver failure and cirrhosis are characterized by abnormal hemostasis with aberrant platelet activation. In particular, the consequences of cholestatic liver disease and molecular mechanisms, including the role of bile acids leading to impaired platelet responses, are not well understood. Here, we demonstrate that bile acids inhibit human and murine platelet activation, adhesion and spreading, leading to reduced thrombus formation under flow conditions. We identified the G-protein coupled receptor TGR5 in platelets and provide support for its role as mediator of bile acid-induced impairment of platelet activation. In the liver, TGR5 couples to Gαs proteins, activates the adenylate cyclase to induce a transient cAMP rise and stimulates the MAPK signaling pathway to regulate cholangiocyte proliferation, hepatocyte survival and inflammation. In this report, we demonstrate that the genetic deficiency of TGR5 in mice led to enhanced platelet activation and thrombus formation, suggesting that TGR5 plays an important role in hemostasis. Mechanistically, platelet inhibition is achieved by TGR5 mediated PKA activation and modulation of AKT and ERK1/2 phosphorylation. Thus, this report provides evidence for the ability of TGR5 ligands to reduce platelet activation and identifies TGR5 agonism as a new target for the prevention of cardiovascular diseases.

Damage-Associated Molecular Patterns as Mediators of Thrombus Formation on Dialyzer Membrane in Critically Ill Patients.

This prospective study investigated the relationship between inflammation, damage-associated molecular patterns (DAMPs), and thrombus formation on dialyzer membranes in critically ill patients undergoing renal replacement therapy (RRT) from July 2020 to August 2022, identifying mechanisms and interventions to prevent clotting. The patients were divided into two groups: inflammatory (n = 56, serum C-reactive protein >10 mg/dl) and noninflammatory control (n = 45, serum C-reactive protein <5 mg/dl). Cell-free deoxyribonucleic acid (DNA) levels, high mobility group box 1 protein (HMGB1), histone H3, and myeloperoxidase (MPO) in the lumen of the hollow fiber membrane of the dialyzer were quantified. Immunostaining assessed leukocytes, fibrin fibers, and platelet thrombi on the luminal surface of the hollow fiber membrane. The inflammatory group, compared to controls, exhibited elevated cell-free DNA, HMGB1, and MPO levels, although histone H3 remained unchanged. Damage-associated molecular patterns increased with disseminated intravascular coagulation (DIC) severity. Immunostaining in the inflammatory group revealed leukocytes, amorphous nuclei, neutrophil extracellular trap-like structures, fibrin fibers, and platelet thrombi on the hollow fiber membrane's luminal surface. Elevated DAMP levels in severely inflamed patients' dialyzer membranes, correlating with DIC severity, indicate a link between inflammation, coagulation activation, and dialyzer clotting. Research into thrombus prevention in RRT for DIC-affected critically ill patients is warranted.

Zhilong Huoxue Tongyu Capsule Ameliorates Platelet Aggregation and Thrombus Induced by Aspirin in Rats by Regulating Lipid Metabolism and MicroRNA Pathway.

Zhilong Huoxue Tongyu capsule (ZLHX) is a traditional Chinese medicinal compound preparation, which exhibits obvious therapeutic effects on aspirin resistance (AR). However, the mechanism of ZLHX on AR is rarely reported. This study aimed to explore the therapeutic effects of AR and the underlying mechanisms of ZLHX on AR rats. An AR model was established through treatment with a high-fat, high-sugar, and highsalt diet for 12 weeks and oral administration of aspirin (27 mg/kg/day) and ibuprofen (36 mg/kg/day) in weeks 9-12. The rats were administrated with ZLHX (225, 450, and 900 mg/kg) from week 12 to week 16. Blood samples were collected after the experiment. Thromboelastography analysis was performed, and the levels of triglyceride (TG), total cholesterol (TC), lowdensity lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were determined. Furthermore, the levels of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1α (6- keto-PGF1α) were determined with commercial ELISA kits. Finally, the gene expressions of microRNA- 126-3p (miRNA-126-3p) and miRNA-34b-3p were detected through a real-time quantitative polymerase chain reaction. Results demonstrated that ZLHX significantly inhibited platelet aggregation in the AR rats. Moreover, ZLHX markedly decreased the levels of TC, TG, and LDL-C and increased the level of HDL-C. Meanwhile, ELISA results confirmed that ZLHX can elevate the expression levels of TXB2 and 6-keto-PGF1α. Further studies suggested that ZLHX significantly downregulated the expression levels of miRNA-126-3p and miRNA-34b-3p. This study revealed that the therapeutic effect of ZLHX might be related to the regulation of lipid metabolism and the miRNA pathway.

Investigation of the impact of thirdhand e-cigarette exposure on platelet function: A pre-clinical study.

The use of e-cigarettes (ECs) has reached unprecedented levels, due to a variety of reasons, including the misconception regarding their safety. Thus, there have been efforts to characterize the effects of EC exposure, including in the context of thirdhand EC (THEC) on a host of disorders, such as cardiovascular disease (CVD). To address this issue, we sought to characterize the effects of THEC on platelet function and thrombus formation, using a novel mouse exposure protocol that resembles real life scenarios. To assess these effects, a host of related in vivo (i.e. tail bleeding time, and ferric chloride injury induced thrombosis model) assays and in vitro platelet specific (e.g. aggregation, and dense granule secretion) investigative assays were conducted. Our in vivo characterization demonstrated that THEC exposed mice exhibited a prothrombotic phenotype reflected by their shortened tail bleeding (THEC: 37 ± 15 seconds, versus clean air: 183 ± 56 s) and occlusion times (THEC: 188 ± 39 s, versus clean air: 519 ± 70 s), relative to those exposed to clean air. Importantly, we found no difference in the platelet counts between the THEC and clean air mice. As for the underlying mechanism, separate experiments revealed significantly enhanced platelet aggregation, dense and alpha granule secretion, as well as integrin/GPIIb-IIIa activation and phosphatidylserine exposure in response to thrombin and ADP agonist stimulation. Taken together, these results provide evidence that THEC does have the capacity to increase the risk of thrombotic disease, which should increase awareness regarding its underappreciated negative health effects.

Prognostic value and immunological role of MMRN1: a rising star in cancer

Background Multimerin 1 (MMRN1) is a factor V binding protein, which can support platelet adhesion and thrombus formation. In recent years, the role of MMRN1 in cancer has begun to attract attention. But systematic studies in this area are lacking. Therefore, we used bioinformatics methods to analyze MMRN1 in tumors to reveal the possible role of MMRN1. Methods Using the Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database, we obtained relevant data for analyzing MMRN1. Using Gene Expression Profiling Interactive Analysis (GEPIA), Human Protein Atlas (HPA), TCGA, GeneMANIA, and cBioPortal, we explored the potential role of MMRN1 in different types of tumors. Tumor Immune System Interactions and Drug Bank (TISIDB) and Sangerbox were used to analyze the correlation between MMRN1 and tumor immunity. Gene set cancer analysis (GSCA) and UALCAN were used to analyze the methylation of MMRN1. GSCA was also used to analyze the drug sensitivity of MMRN1. Results MMRN1 is down-regulated in most cancer types and is closely related to the prognosis of cancer patients. Interestingly, in most tumors, MMRN1 is positively correlated with immune -related genes. In addition, we observed different levels of methylation and mutations in different types of tumors. Drug sensitivity analysis found that MMRN1 was negatively correlated with several drugs, including GW-2580 and TL-1-85, suggesting that it can be used to develop potential anticancer therapies. Conclusion Our analysis demonstrated a significant relationship between MMRN1 and prognosis, tumor immunity, and drug sensitivity of several tumors. As a rising star in cancer, it needs further research.

Impact of antiplatelet therapy on microvascular thrombosis during ST-elevation myocardial infarction.

During an acute coronary syndrome, atherosclerotic plaque rupture triggers platelet activation and thrombus formation, which may completely occlude a coronary artery leading to ST-elevation myocardial infarction (STEMI). Although emergency percutaneous coronary intervention (PCI) is effective in re-opening the main coronary arteries, the downstream microvasculature can become obstructed by embolised plaque material and thrombus. Dual antiplatelet therapy is recommended by guidelines and used routinely for the management of STEMI to reduce the risk of recurrent atherothrombotic events. However it is unclear to what extent antiplatelet therapy reduces microvascular thrombosis, largely because most tools to assess microvascular thrombosis only became available after antiplatelet therapy was already used in the majority of patients. Platelets play a central role in key aspects of microvascular thrombosis, such as atherosclerotic plaque-induced thrombus development, inflammation and microvascular dysfunction, making them a potential target for novel therapeutic interventions. Currently, more potent antiplatelet agents like GPIIb/IIIa inhibitors may be administered during PCI directly into coronary arteries with high thrombus burden but it is not well-established whether this reduces microvascular thrombosis and they significantly increase the risk of bleeding. In this review article we discuss the role of platelets in microvascular thrombosis, describe how microvascular thrombosis and obstruction can be assessed clinically and explore potential new antiplatelet treatments for this. In particular, we highlight novel antiplatelet drugs targeting the platelet receptor GPVI, as well as PAR4, GPIb-IX-V and 5HT2A receptors. We also discuss the potential benefit of P-selectin inhibitors as they have proven to be effective in reducing microvascular thrombosis in sickle-cell disease which could translate into potential benefits in acute coronary syndrome.

Evaluation of the EMBOPIPE flow diverter device: in vivo and in vitro experiments

BackgroundAlthough flow diverter device (FDD) has brought revolutionized advances in endovascular treatment of intracranial aneurysms, it also presents considerable drawbacks as well, as the innovation for novel device has never stopped. This preclinical research aims to evaluate the safety and efficacy of a newly developed FDD, the EMBOPIPE, through in vivo and in vitro experiments.MethodsAneurysms were induced in 20 New Zealand white rabbits which were randomized to three follow-up groups according to the time elapsed after EMBOPIPE implantation (28, 90, and 180 days). Additional EMBOPIPEs were implanted in the abdominal aorta to cover the renal artery in nine rabbits. Angiography was performed immediately after device placement in all groups. Aneurysm occlusion, patency of renal arteries, and pathological outcomes were assessed. For the in vitro experiments, we measured the thrombogenic potential of EMBOPIPEs (n = 5) compared with bare stents (n = 5) using the Chandler loop model. Evaluation indicators were the platelet counts, macroscopic observations and scanning electron microscopy.ResultsEMBOPIPEs were successfully deployed in 19 of 20 rabbit aneurysms (95.0%). The rates of complete or near-complete aneurysm occlusion were 73.3%, 83.3%, and 100% in the 28-, 90-, and 180-day groups, respectively. All renal arteries covered by EMBOPIPEs remained patent, and the mean difference in renal artery diameter before and after the device placement in the three groups was 0.07 mm, 0.10 mm, and 0.10 mm, respectively (p = 0.77). Renal pathology was normal in all cases. The pathological findings of the aneurysms were as follows: thickened and adequate neointimal coverage at the aneurysm neck, minimal inflammatory response, near-complete smooth muscle cell layer, and endothelialization along the device. In vitro experiments showed that the platelet counts were significantly higher in EMBOPIPE blood samples than in bare stent samples and that platelet adhesion to the device was lower in the EMBOPIPE stent struts compared with bare stent struts through macroscopic observations and scanning electron microscopy.ConclusionsThe EMBOPIPE can achieve high rates of aneurysm occlusion while maintaining excellent branch artery patency. It exhibited wonderful pathological results. This novel device with phosphorylcholine surface modification could reduce platelet thrombus attached to the stent struts.

Elucidating the distinctive regulatory effects and mechanisms of active compounds in Salvia miltiorrhiza Bunge via network pharmacology: Unveiling their roles in the modulation of platelet activation and thrombus formation

Salvia miltiorrhiza Bunge. (DS), as an important traditional Chinese medicine (TCM), has a long history of usage for promoting blood circulation and removing blood stasis. Modern studies have shown that the chemical components of DS have many biological activities such as cardiovascular protection, anti-arrhythmia, anti-atherosclerosis, improvement of microcirculation, protection of myocardium, inhibition and removal of platelet aggregation. Nevertheless, the action mechanism of DS as well its active compounds on platelet activation has not been fully uncovered. This study aimed to find out the potential targets and mechanisms of DS in the modulation of platelet activation and thrombosis, using network pharmacology and biological experimental. These compounds with anti-thrombotic activity in DS, cryptotanshinone (CPT), isoeugenol (ISO) and tanshinone IIA (TSA), together with the corresponding targets being Src, Akt and RhoA are screened by network pharmacology. We confirmed that ISO, CPT and TSA dose-dependently inhibited platelet activation in vitro, mainly by inhibiting agonist-induced clot retraction, aggregation and P-selectin and ATP release. The western blot findings indicated that ISO, CPT, and TSA led to reduced levels of p-Akt and p-ERK in activated platelets. Additionally, ISO and TSA were observed to decrease p-cSrc expression while increasing RhoA expression. ISO, CPT, and TSA demonstrated a potential to restrict the advancement of carotid arterial thrombosis in vivo. We confirm that ISO, CPT and TSA are the key anti-thrombotic active compounds in DS. These active compounds exhibit unique inhibitory effects on platelet activation and thrombus formation by modulating the Akt/ERK and cSrc/RhoA signaling pathways.