Platelet Aggregation Research Articles

The shear rate promotes pinocytosis of extracellular dextran in platelets.

Several conventional studies focused on platelet pinocytosis for possible utilization as drug delivery systems. Although platelet pinocytosis is important in such utilization, the impact of the shear rate on pinocytosis is unclear. Our objective was to investigate the relationship between shear rate and platelet pinocytosis in vitro. In addition, this study addressed the change in platelet aggregation reactivity with adenosine diphosphate (ADP) stimulation after pinocytosis. Porcine platelet-rich plasma was mixed with fluorescein isothiocyanate (FITC)-conjugated dextran and incubated for 15 min under shear conditions of 0, 500, and 1500 s-1. After incubation, confocal microscopic scanning and three-dimensional rendering were performed to confirm the internalization of FITC-dextran into platelets. The amount of FITC-dextran accumulated via platelet pinocytosis was compared using flow cytometry at each shear rate. In addition, light transmission aggregometry by ADP stimulation was applied to platelets after pinocytosis. The amount of intracellular FITC-dextran increased with higher shear rates. Platelets with increased amounts of intracellular FITC-dextran did not show changes in the aggregation reactivity to ADP. A higher shear rate promotes platelet pinocytosis, but enhanced pinocytosis does not affect aggregation sensitivity, which is stimulated by ADP.

The association between abcb1 gene polymorphism and clopidogrel response variability in stroke ischemic: a cross sectional study

BackgroundClopidogrel has been the primary choice of antiplatelet in ischemic stroke that inhibits adenosine diphosphate (ADP)-induced platelet aggregation. P-glycoprotein (P-gp) multidrug resistance-1 (MDR1) is a transmembrane efflux transporter in intestinal cells that plays a significant role in clopidogrel absorption, therefore may affect platelet aggregation. P-gp is encoded by the ABCB1 gene. This study aims to evaluate the effect of ABCB1 polymorphism on clopidogrel response variability in ischemic stroke patients and its genotype frequency.MethodsA cross-sectional study was conducted in ischemic stroke patients who received clopidogrel between 2020 and 2023 in RSUI/RSCM. All subjects were assessed for ABCB1 polymorphisms C3435T and C1236T. Platelet aggregation were measured using VerifyNow PRU. Clopidogrel response variability was classified into unresponsive (> 208 PRU), responsive (95–208 PRU), and bleeding risk (< 95 PRU).Results124 subjects enrolled in this study, with 12,9% of subjects classified as non-responsive/resistant, 49,5% as responsive, and 41,9% as bleeding risk. ABCB1 C1236T homozygote wildtype (CC) was associated with 3,76 times higher bleeding risk than other variants (p = 0,008; 95%CI 1,41 − 10,07). Genotype frequency of ABCB1 C3435T homozygote wildtype, heterozygote, and homozygote variants were 35,9%, 43,5% and 16,9%, respectively; while the genotype frequency of ABCB1 C1236T were 17,8%, 39,5%, and 42,7%, respectively.ConclusionABCB1 C1236T homozygote wildtype was associated with 3,76 times higher bleeding risk than other variants. The most common genotype frequency of ABCB1 C1236T was homozygote variant; while for ABCB1 C3435T was heterozygote.

Blunt Trauma Induced Closed Femoral Bone Fracture in a Rat Model: Are Vessels Safe to Use for Microsurgery? Further Insight into the Zone of Injury Concept.

The study aims to investigate the zone of injury for major vessels after high-velocity traumas, as it is unclear whether avoiding vascular structures is necessary during microvascular anastomosis or how long it takes for them to be used again. This study uses Doppler ultrasonography and a rat model to evaluate the histopathological changes and flow velocity of major vessels in the zone of injury after high-velocity trauma with closed femoral bone fracture. Osteosynthesis was performed using an intramedullary wire. Samples were collected from day 3 and week 3. The unaffected contralateral side is used as control. Results from arterial and venous flow assessments showed no evidence of ischemia in the extremities. Both arteries and veins were patent in both intervals and on the control side. The evaluation of the vessels showed arterial injury with a slightly reduced arterial flow on day 3 and week 3. The venous flow was slightly reduced on day 3 but not on week 3. Statistically, arterial endothelial injury was higher on day 3 than on week 3 (p = 0.006). Media inflammation was also higher on day 3 (p = 0.06). Arterial endothelization distribution was higher in week 3 (p = 0.006). No significant differences were found in arterial media irregularity, necrosis, platelet aggregation, bleeding, and wall rupture. Venous samples showed no significant differences in any parameter (p < 0.05). High-velocity trauma increases the risk of thrombosis in vessels. Intravascular repair can start on day 2 and continue till week 3 with significant endothelization. Although physiologic findings do not alter arterial or venous flow, histologic findings support vessel injuries leading to potential complications. Microsurgery should be considered out of the injury zone until adequate vessel healing is achieved.

Formulation Development and Evaluation of Ticagrelor Oral Dispersible Tablets by Using Co-processed Superdisintegrants

Ticagrelor is a contemporary anti-platelet drug that inhibits the aggregation of platelets by blocking the adenosine phosphate (ADP) receptors of the subtype P2Y12; generally utilized in patients who have a previous history of myocardial infarction or with acute coronary syndrome to prevent occurring of myocardial infarction, cardiovascular death and stroke in future. This study focuses on the development of formulation development &amp; assessment of an oral dispersible tablet of ticagrelor, a Biopharmaceutical Classification System (BCS) class 4 drug, by using the co-processed superdisintegrants to enhance drug dissolution and bioavailability. Wet granules with different concentrations of co-processed superdisintegrants developed the tablets. This study includes seven formulations that were formulated using the different selected excipients. The various batches were assessed for physical characteristics, disintegration, dissolution studies, hardness and friability. In-vitro dissolution investigations were conducted for formulations. S1 to S7 at time points 5, 15 and 30 minutes. According to the results of the formulation S7 was discovered to be the optimum formulation, as shown 102.89% drug release at 5 minutes and a disintegration time of 16 seconds. Thus, it appears that S7 is the most suitable formulation of ticagrelor oral dispersible tablet in order for enhanced bioavailability.

Characterization of Unique Pathological Features of COVID-Associated Coagulopathy: Studies with AC70 hACE2 Transgenic Mice Highly Permissive to SARS-CoV-2 Infection.

COVID-associated coagulopathy seemly plays a key role in post-acute sequelae of SARS- CoV-2 infection. However, the underlying pathophysiological mechanisms are poorly understood, largely due to the lack of suitable animal models that recapitulate key clinical and pathological symptoms. Here, we fully characterized AC70 line of human ACE2 transgenic (AC70 hACE2 Tg) mice for SARS-CoV-2 infection. We noted that this model is highly permissive to SARS-CoV-2 with values of 50% lethal dose and infectious dose as ~ 3 and ~ 0.5 TCID50 of SARS-CoV-2, respectively. Mice infected with 105 TCID50 of SARS-CoV-2 rapidly succumbed to infection with 100% mortality within 5 days. Lung and brain were the prime tissues harboring high viral titers, accompanied by histopathology. However, viral RNA and inflammatory mediators could be detectable in other organs, suggesting the nature of a systemic infection. Lethal challenge of AC70 hACE2 Tg mice caused acute onset of leukopenia, lymphopenia, along with an increased neutrophil-to-lymphocyte ratio (NLR). Importantly, infected animals recapitulated key features of COVID-19-associated coagulopathy. SARS-CoV-2 could induce the release of circulating neutrophil extracellular traps (NETs), along with activated platelet/endothelium marker. Immunohistochemical staining with anti-platelet factor-4 (PF4) antibody revealed profound platelet aggregates especially within blocked veins of the lungs. We showed that acute SARS-CoV-2 infection triggered a hypercoagulable state coexisting with ill-regulated fibrinolysis. Finally, we highlighted the potential role of Annexin A2 (ANXA2) in fibrinolytic failure. ANXA2 is a calcium-dependent phospholipid-binding protein that forms a heterotertrameric complexes localized at the extracellular membranes with two S100A10 small molecules acting as a co-receptor for tissue-plasminogen activator (t-PA), tightly involved in cell surface fibrinolysis. Thus, our results revealing elevated IgG type anti-ANXA2 antibody production, downregulated de novo ANXA2/S100A10 synthesis, and reduced ANXA2/S100A10 association in infected mice, this protein might serve as druggable targets for development of antithrombotic and/or anti-fibrinolytic agents to attenuate pathogenesis of COVID-19.

Intraplatelet miRNA-126 regulates thrombosis and its reduction contributes to platelet inhibition.

MicroRNA-126 (miR-126), one of the most abundant microRNAs in platelets, is involved in the regulation of platelet activity and the circulating miR-126 is reduced during antiplatelet therapy. However, whether intraplatelet miR-126 plays a role in thrombosis and platelet inhibition remains unclear. Here, using tissue-specific knockout mice, we reported that the deficiency of miR-126 in platelets and vascular endothelial cells significantly prevented thrombosis and prolonged bleeding time. Using chimeric mice, we identified that the lack of intraplatelet miR-126 significantly prevented thrombosis. Ex vivo experiments further demonstrated that miR-126-deficient platelets displayed impaired platelet aggregation, spreading and secretory functions. Next, miR-126 was confirmed to target phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2) in platelet, which encodes a negative regulator of the PI3 K/AKT pathway, enhancing platelet activation through activating the integrin αIIbβ3-mediated outside-in signaling. After undergoing myocardial infarction (MI), chimeric mice lacking intraplatelet miR-126 displayed reduced microvascular obstruction and prevented MI expansion in vivo. In contrast, overexpression of miR-126 by the administration of miR-126 agonist (agomiR-126) in wild-type mice aggravated microvascular obstruction and promoted MI expansion, which can be almost abolished by aspirin administration. In patients with cardiovascular diseases, antiplatelet therapies, either aspirin alone or combined with clopidogrel, decreased the level of intraplatelet miR-126. The reduction of intraplatelet miR-126 level was associated with the decrease of platelet activity. Our murine and human data reveal that (i) intraplatelet miR-126 contributes to platelet activity and promotes thrombus formation, and (ii) the reduction of intraplatelet miR-126 contributes to platelet inhibition during antiplatelet therapy.

Reduction of ristocetin-induced platelet aggregation (RIPA) during storage despite plasma renewal: evidence for hemostatic importance of GPIbα shedding

ABSTRACT Background Platelet storage is complicated by deleterious changes, among which reduction of ristocetin-induced platelet aggregation (RIPA) has a poorly understood mechanism. The study elucidates the mechanistic roles of all the possible players in this process. Research design and methods PRP-platelet concentrates were subjected to RIPA, collagen-induced platelet aggregation (CIPA), and flowcytometric analysis of GPIbα and PAC-1 binding from days 0 to 5 of storage. Platelet-poor plasma was subjected to colorimetric assays for glucose/LDH evaluation and automatic analyzer to examine VWF antigen and activity. Results From day three of platelet storage, reducing CIPA but not RIPA was correlated with the reduction of both metabolic state and integrin activity. RIPA reduction was directly related to the decreased levels of total-content/expression of GPIbα, and inversely related to its shedding levels during storage. Re-suspension of 5-day stored platelet in fresh plasma compensated CIPA, but not RIPA. VWF concentration and its activity did not change during storage while they had no correlation with RIPA. Conclusions This study identified the irreversible loss of platelet GPIbα, but not VWF status, as the primary cause of the storage-dependent decrease of RIPA. Unlike CIPA, this observation was not compensated by plasma refreshment, suggesting that some evidence of PSL may not be recovered after transfusion.

Developing a Biomimetic 3D Neointimal Layer as a Prothrombotic Substrate for a Humanized In Vitro Model of Atherothrombosis.

Acute cardiovascular events result from clots caused by the rupture and erosion of atherosclerotic plaques. This paper aimed to produce a functional biomimetic hydrogel of the neointimal layer of the atherosclerotic plaque that can support thrombogenesis upon exposure to human blood. A biomimetic hydrogel of the neointima was produced by culturing THP-1-derived foam cells within 3D collagen hydrogels in the presence or absence of atorvastatin. Prothrombin time and platelet aggregation onset were measured after exposure of the neointimal models to platelet-poor plasma and washed platelet suspensions prepared from blood of healthy, medication-free volunteers. Activity of the extrinsic coagulation pathway was measured using the fluorogenic substrate SN-17. Foam cell formation was observed following preincubation of the neointimal biomimetic hydrogels with oxidized LDL, and this was inhibited by pretreatment with atorvastatin. The neointimal biomimetic hydrogel was able to trigger platelet aggregation and blood coagulation upon exposure to human blood products. Atorvastatin pretreatment of the neointimal biomimetic layer significantly reduced its pro-aggregatory and pro-coagulant properties. In the future, this 3D neointimal biomimetic hydrogel can be incorporated as an additional layer within our current thrombus-on-a-chip model to permit the study of atherosclerosis development and the screening of anti-thrombotic drugs as an alternative to current animal models.

Identification of differentially expressed genes to predict the risk of heart failure in older patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a common heart disease. Old people with HCM are at high risk of heart failure (HF). This study aimed to identify differentially expressed genes (DEGs) to evaluate the risk of HF in older patients with HCM. GSE89714 and GSE116250 were downloaded from Gene Expression Omnibus (GEO) database, and DEGs were identified by using limma R package with P < 0.05 and logFC> 1 as cut off. Protein-protein interaction (PPI) network, Genome Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed for the identified DEGs. NetworkAnalyst online tool was applied for Gene Set Enrichment Analysis (GSEA) analysis. We identified 124 overlap DEGs from the 2 datasets. PPI network showed that COL1A1, COL3A1, COL1A2, BGN, COL5A1, LUM, TGFB2, FMOD, ASPN, and COL14A1 were the top ten genes related to HCM and HF compared with control. Functional and pathway analyses showed that the overlap genes were mainly related to ECM-receptor interaction, ECM organization, Focal adhesion, PI3K-Akt signaling, TGF-beta signaling, and Platelet activation signaling and aggregation. Among the overlap genes, COL5A1 and LUM were significantly upregulated, while TGFB2, FMOD, ASPN, and COL14A1 were significantly downregulated in HF dataset compared with HCM dataset. Bioinformatics-based analysis revealed potential genes associated with HCM and HF, which could be utilized to evaluate the risk of HF in older patients with HCM.

CYP2C19 Genetic Testing for Oral P2Y12 Inhibitor Therapy: A Scientific Statement From the American Heart Association.

There is significant variability in the efficacy and safety of oral P2Y12 inhibitors, which are used to prevent ischemic outcomes in common diseases such as coronary and peripheral arterial disease and stroke. Clopidogrel, a prodrug, is the most used oral P2Y12 inhibitor and is activated primarily after being metabolized by a highly polymorphic hepatic cytochrome CYP2C219 enzyme. Loss-of-function genetic variants in CYP2C219 are common, can result in decreased active metabolite levels and increased on-treatment platelet aggregation, and are associated with increased ischemic events on clopidogrel therapy. Such patients can be identified by CYP2C19 genetic testing and can be treated with alternative therapy. Conversely, universal use of potent oral P2Y12 inhibitors such as ticagrelor or prasugrel, which are not dependent on CYP2C19 for activation, has been recommended but can result in increased bleeding. Recent clinical trials and meta-analyses have demonstrated that a precision medicine approach in which loss-of-function carriers are prescribed ticagrelor or prasugrel and noncarriers are prescribed clopidogrel results in reducing ischemic events without increasing bleeding risk. The evidence to date supports CYP2C19 genetic testing before oral P2Y12 inhibitors are prescribed in patients with acute coronary syndromes or percutaneous coronary intervention. Clinical implementation of such genetic testing will depend on among multiple factors: rapid availability of results or adoption of the concept of performing preemptive genetic testing, provision of easy-to-understand results with therapeutic recommendations, and seamless integration in the electronic health record.

Physiological platelet aggregation assay to mitigate drug-induced thrombocytopenia using a microphysiological system

Developing a reliable method to predict thrombocytopenia is imperative in drug discovery. Here, we establish an assay using a microphysiological system (MPS) to recapitulate the in-vivo mechanisms of platelet aggregation and adhesion. This assay highlights the role of shear stress on platelet aggregation and their interactions with vascular endothelial cells. Platelet aggregation induced by soluble collagen was detected under agitated, but not static, conditions using a plate shaker and gravity-driven flow using MPS. Notably, aggregates adhered on vascular endothelial cells under gravity-driven flow in the MPS, and this incident increased in a concentration-dependent manner. Upon comparing the soluble collagen-induced aggregation activity in platelet-rich plasma (PRP) and whole blood, remarkable platelet aggregate formation was observed at concentrations of 30 µg/mL and 3 µg/mL in PRP and whole blood, respectively. Moreover, ODN2395, an oligonucleotide, induced platelet aggregation and adhesion to vascular endothelial cells. SYK inhibition, which mediated thrombogenic activity via glycoprotein VI on platelets, ameliorated platelet aggregation in the system, demonstrating that the mechanism of platelet aggregation was induced by soluble collagen and oligonucleotide. Our evaluation system partially recapitulated the aggregation mechanisms in blood vessels and can contribute to the discovery of safe drugs to mitigate the risk of thrombocytopenia.

Potent inhibitory effect on human platelet aggregation of the aerial part of Canna edulis

Canna edulis Ker Gawl has been used in Vietnamese Traditional Medicine for the treatment of heart diseases with very limited scientific evidence. This study aimed to evaluate the inhibitory effect on human platelet aggregation of the aerial part of C. edulis. Aerial C. edulis was firstly macerated with methanol, and then fractionated with different solvents to obtain 3 fractions: n-hexane, ethyl acetate and aqueous extracts. The inhibitory effects on human platelet aggregation of extracts were evaluated via three parameters: percentage inhibition of platelet aggregation (%I), area under the aggregation curve (AUC) and aggregation slope, using two agonists adenosine diphosphate (ADP) and collagen. The results showed that all extracts significantly inhibited platelet aggregation in a dose-dependent manner for both agonists. Moreover, all extracts significantly decreased AUC and slope, indicating their antiaggregatory effects on both general aggregation and aggregation velocity. Among extracts, the ethyl acetate fraction exhibited the strongest effect regardless of agonists used (%I at 4 mg/mL, 99.2% for both ADP and collagen). The n-hexane fraction also had significant inhibitory effect but it was weaker than the others (p &lt; 0.05). This is the first study to demonstrate the potent antiplatelet effect of the aerial part of C. edulis. This plant could be a potential natural source for searching novel antiplatelet agents and developing dietary supplements for management of cardiovascular diseases.

Synergistic effect of protein foams and polysaccharide on the invisible hemostasis of acellular dermal matrix sponges

Efficient management of hemorrhage is vital for preventing hemorrhagic shock and safeguarding wounds against infection. Inspired by the traditional Chinese steamed bread-making process, which involves kneading, foaming, and steaming, we devised a hemostatic sponge by amalgamating an acellular dermal matrix gel, hydroxyethyl starch, and rice hydrolyzed protein. The integration of hydroxyethyl starch bolstered the sponge's mechanical and hemostatic attributes, while the inclusion of rice hydrolyzed protein, acting as a natural foaming agent, enhanced its porosity This augmentation facilitated rapid blood absorption, accelerated clot formation, and stimulated the clotting cascade. Experimental findings underscore the exceptional biocompatibility and physicochemical characteristics of the hemostatic sponge, positioning it on par with commercially available collagen hemostatic sponges for hemorrhage control. Mechanistically, the sponge fosters aggregation and activation of red blood cells and platelets, expediting coagulation kinetics both in vivo and in vitro. Notably, this hemostatic sponge activates the clotting cascade sans crosslinking agents, offering a premium yet cost-effective biomaterial with promising clinical applicability.

Hydrogen Sulfide Promotes Platelet Autophagy via PDGFR-α/PI3K/Akt Signaling in Cirrhotic Thrombocytopenia.

The role of platelet autophagy in cirrhotic thrombocytopenia (CTP) remains unclear. This study aimed to investigate the impact of platelet autophagy in CTP and elucidate the regulatory mechanism of hydrogen sulfide (H2S) on platelet autophagy. Platelets from 56 cirrhotic patients and 56 healthy individuals were isolated for in vitro analyses. Autophagy markers (ATG7, BECN1, LC3, and SQSTM1) were quantified using enzyme-linked immunosorbent assay, while autophagosomes were visualized through electron microscopy. Western blotting was used to assess the autophagy-related proteins and the PDGFR/PI3K/Akt/mTOR pathway following treatment with NaHS (an H2S donor), hydroxocobalamin (an H2S scavenger), or AG 1295 (a selective PDGFR-α inhibitor). A carbon tetrachloride-induced cirrhotic BALB/c mouse model was established. Cirrhotic mice with thrombocytopenia were randomly treated with normal saline, NaHS, or hydroxocobalamin for 15 days. Changes in platelet count and aggregation rate were observed every three days. Cirrhotic patients with thrombocytopenia exhibited significantly decreased platelet autophagy markers and endogenous H2S levels, alongside increased platelet aggregation, compared to healthy controls. In vitro, NaHS treatment of platelets from severe CTP patients elevated LC3-II levels, reduced SQSTM1 levels, and decreased platelet aggregation in a dose-dependent manner. H2S treatment inhibited PDGFR, PI3K, Akt, and mTOR phosphorylation. In vivo, NaHS significantly increased LC3-II and decreased SQSTM1 expressions in platelets of cirrhotic mice, reducing platelet aggregation without affecting the platelet count. Diminished platelet autophagy potentially contributes to thrombocytopenia in cirrhotic patients. H2S modulates platelet autophagy and functions possibly via the PDGFR-α/PI3K/Akt/mTOR signaling pathway.

Angiopoietin-like protein 2 inhibits thrombus formation.

Acute myocardial infarction is mainly caused by a lack of blood flood in the coronary artery. Angiopoietin-like protein 2 (ANGPTL2) induces platelet activation and thrombus formation in vitro through binding with immunoglobulin-like receptor B, an immunoglobulin superfamily receptor. However, the mechanism by which it regulates platelet function in vivo remains unclear. In this study, we investigated the role of ANGPTL2 during thrombosis in relationship with ST-segment elevation myocardial infarction (STEMI) with spontaneous recanalization (SR). In a cohort of 276 male and female patients, we measured plasma ANGPTL2 protein levels. Using male Angptl2-knockout and wild-type mice, we examined the inhibitory effect of Angptl2 on thrombosis and platelet activation both in vivo and ex vivo. We found that plasma and platelet ANGPTL2 levels were elevated in patients with STEMI with SR compared to those in non-SR (NSR) patients, and was an independent predictor of SR. Angptl2 deficiency accelerated mesenteric artery thrombosis induced by FeCl3 in Angptl2-/- compared to WT animals, promoted platelet granule secretion and aggregation induced by thrombin and collogen while purified ANGPTL2 protein supplementation reversed collagen-induced platelet aggregation. Angptl2 deficiency also increased platelet spreading on immobilized fibrinogen and clot contraction. In collagen-stimulated Angptl2-/- platelets, Src homology region 2 domain-containing phosphatase (Shp)1-Y564 and Shp2-Y580 phosphorylation were attenuated while Src, Syk, and Phospholipase Cγ2 (PLCγ2) phosphorylation increased. Our results demonstrate that ANGPTL2 negatively regulated thrombus formation by activating ITIM which can suppress ITAM signaling pathway. This new knowledge provides a new perspective for designing future antiplatelet aggregation therapies.

Aspirin suppresses hepatocellular carcinoma progression by inhibiting platelet activity.

Hepatocellular carcinoma (HCC) is the most common malignant liver disease in the world. Platelets (PLTs) are known to play a key role in the maintenance of liver homeostasis and the pathophysiological processes of a variety of liver diseases. Aspirin is the most classic antiplatelet agent. However, the molecular mechanism of platelet action and whether aspirin can affect HCC progression by inhibiting platelet activity need further study. To explore the impact of the antiplatelet effect of aspirin on the development of HCC. Platelet-rich plasma, platelet plasma, pure platelet, and platelet lysate were prepared, and a coculture model of PLTs and HCC cells was established. CCK-8 analysis, apoptosis analysis, Transwell analysis, and real-time polymerase chain reaction (RT-PCR) were used to analyze the effects of PLTs on the growth, metastasis, and inflammatory microenvironment of HCC. RT-PCR and Western blot were used to detect the effects of platelet activation on tumor-related signaling pathways. Aspirin was used to block the activation and aggregation of PLTs both in vitro and in vivo, and the effect of PLTs on the progression of HCC was detected. PLTs significantly promoted the growth, invasion, epithelial-mesenchymal transition, and formation of an inflammatory microenvironment in HCC cells. Activated PLTs promoted HCC progression by activating the mitogen-activated protein kinase/protein kinase B/signal transducer and activator of transcription three (MAPK/ AKT/STAT3) signaling axis. Additionally, aspirin inhibited HCC progression in vitro and in vivo by inhibiting platelet activation. PLTs play an important role in the pathogenesis of HCC, and aspirin can affect HCC progression by inhibiting platelet activity. These results suggest that antiplatelet therapy has promising application prospects in the treatment and combined treatment of HCC.

Obliteration of liver sinusoids through platelet aggregates associated to extramedullary haematopoiesis in myeloid neoplasms.

Herein is reported a series of five patients with myeloid neoplasms presenting hepatic complications in whose liver biopsy revealed obstruction of sinusoids by platelet aggregates associated to liver extramedullary haematopoiesis. Indication of liver biopsies was jaundice, unexplained hepatomegaly or portal hypertension. Haematological disorders were classified according to the World Health Organisation. Molecular profile was established in all cases as well as grade of liver extramedullary haematopoiesis and myelofibrosis. The patients were four men and one woman aged from 50 to 82years. Two patients had myeloproliferative neoplasm (triple negative primary myelofibrosis and JAK2-mutated essential thrombocytopenia), two patients had unclassifiable myelodysplastic/myeloproliferative neoplasm and one patient had chronic myelomonocytic leukaemia type 1. Liver biopsies revealed platelet aggregates occluding sinusoids in association with extramedullary haematopoiesis grade 1 in one patient, grade 2 in two patients and grade 3 in two patients. Two of these patients presented co-existing liver fibrosis due to chronic alcoholic consumption and ischemic heart failure. These five patients died from 2 to 23months after liver biopsy due to acute myeloblastic leukaemia (three patients), portal hypertension (one patient) or other causes (acute heart failure). Intrahepatic sinusoidal microthromboses through platelet aggregates might cause portal hypertension or liver deficiency in patients with myeloid neoplasms, independently of JAK2 mutational status and grade of extramedullary haematopoiesis.

Role and recent progress of P2Y12 receptor in cancer development.

P2Y12 receptor (P2Y12R) is an adenosine-activated G protein-coupled receptor (GPCR) that plays a central role in platelet function, hemostasis, and thrombosis. P2Y12R activation can promote platelet aggregation and adhesion to cancer cells, promote tumor angiogenesis, and affect the tumor immune microenvironment (TIME) and tumor drug resistance, which is conducive to the progression of cancers. Meanwhile, P2Y12R inhibitors can inhibit this effect, suggesting that P2Y12R may be a potential therapeutic target for cancer. P2Y12R is involved in cancer development and metastasis, while P2Y12R inhibitors are effective in inhibiting cancer. However, a new study suggests that long-term use of P2Y12R inhibitors may increase the risk of cancer and the mechanism remains to be explored. In this paper, we reviewed the structural and functional characteristics of P2Y12R and its role in cancer. We explored the role of P2Y12R inhibitors in different tumors and the latest advances by summarizing the basic and clinical studies on the effects of P2Y12R inhibitors on tumors.

Application of Funnel Metadynamics to the Platelet Integrin αIIbβ3 in Complex with an RGD Peptide.

Integrin αIIbβ3 mediates platelet aggregation by binding the Arginyl-Glycyl-Aspartic acid (RGD) sequence of fibrinogen. RGD binding occurs at a site topographically proximal to the αIIb and β3 subunits, promoting the conformational activation of the receptor from bent to extended states. While several experimental approaches have characterized RGD binding to αIIbβ3 integrin, applying computational methods has been significantly more challenging due to limited sampling and the need for a priori information regarding the interactions between the RGD peptide and integrin. In this study, we employed all-atom simulations using funnel metadynamics (FM) to evaluate the interactions of an RGD peptide with the αIIb and β3 subunits of integrin. FM incorporates an external history-dependent potential on selected degrees of freedom while applying a funnel-shaped restraint potential to limit RGD exploration of the unbound state. Furthermore, it does not require a priori information about the interactions, enhancing the sampling at a low computational cost. Our FM simulations reveal significant molecular changes in the β3 subunit of integrin upon RGD binding and provide a free-energy landscape with a low-energy binding mode surrounded by higher-energy prebinding states. The strong agreement between previous experimental and computational data and our results highlights the reliability of FM as a method for studying dynamic interactions of complex systems such as integrin.

Platelet and red cell responses to three North American pit vipers

We investigated the hemotoxic effects of three North American pit vipers in healthy human donor blood. Using experiments focusing on platelet and red blood cell activity, we found differential effects of these venoms on these cellular components. Platelet aggregation was most induced by C. adamanteus. Platelet activation was highest with C. atrox. Red blood cells had calcium expression and erythrocyte formation most induced by C. adamanteus and A. piscivorus. These results demonstrate the complex interplay of individual cellular effects with clinical presentations seen in envenomings from these species.