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Background and Purpose: Although the amphiphilic nature of the widely used antithrombotic drug Ticagrelor is well known, it was never considered as a membranotropic agent capable of interacting with the lipid bilayer in a receptor‐independent way. In this study, we investigated the influence of Ticagrelor on plasma membrane lipid order in platelets and if this modulates the potency of Ticagrelor at the P2Y12 receptor. Experimental Approach: We combined fluorescent in situ, in vitro and in silico approaches to probe the interactions between the plasma membrane of platelets and Ticagrelor. The influence of Ticagrelor on the lipid order of the platelet plasma membrane and large unilamellar vesicles was studied using the advanced fluorescent probe NR12S. Furthermore, the properties of model lipid bilayers in the presence of Ticagrelor were characterized by molecular dynamics simulations. Finally, the influence of an increased lipid order on the dose‐response of platelets to Ticagrelor was studied. Key Results: Ticagrelor incorporates spontaneously into lipid bilayers and affects the lipid order of the membranes of model vesicles and isolated platelets, in a nontrivial composition and concentration‐dependent manner. We showed that higher plasma membrane lipid order in platelets leads to a lower IC50 value for Ticagrelor. It is shown that membrane incorporation of Ticagrelor increases its potency at the P2Y12 receptor, by increasing the order of the platelet plasma membrane. Conclusion and Implications: A novel dual mechanism of Ticagrelor action is suggested that combines direct binding to P2Y12 receptor with simultaneous modulation of receptor‐lipid microenvironment. [ABSTRACT FROM AUTHOR]

Microglia, as immune cells in the central nervous system, possess the ability to adapt morphologically and functionally to their environment. Glymphatic system, the principal waste clearance system in the brain, exhibits circadian rhythms. However, the impact of microglia on the glymphatic system function remains unknown. In this study, we explored the intricate relationship between microglia and the glymphatic system. Examining diurnal patterns, we identified synchronized behaviors in glymphatic activity and microglial morphology, peaking during sleep and exhibiting distinct changes in branching complexity. Depleting microglia using PLX5622 or in P2Y12 knockout mice enhanced glymphatic function. Chemogenetic manipulation of microglia demonstrated that activating HM3D improved glymphatic function, while inhibiting HM4D unexpectedly increased microglial complexity. These findings highlight the dynamic influence of microglia on the glymphatic system. [ABSTRACT FROM AUTHOR]

Background: P2X7 receptor has emerged as a potentially superior PET imaging marker to TSPO, the gold standard for imaging glial reactivity. [11C]SMW139 is the most recently developed radiotracer to image P2X7 receptor. The aim of this study was to image reactive glia in the APP/PS1-21 transgenic (TG) mouse model of Aβ deposition longitudinally using [11C]SMW139 targeting P2X7 receptor and to compare tracer uptake to that of [18F]F-DPA targeting TSPO at the final imaging time point. TG and wild type (WT) mice underwent longitudinal in vivo PET imaging using [11C]SMW139 at 5, 8, 11, and 14 months, followed by [18F]F-DPA PET scan only at 14 months. In vivo imaging results were verified by ex vivo brain autoradiography, immunohistochemical staining, and analysis of [11C]SMW139 unmetabolized fraction in TG and WT mice. Results: Longitudinal change in [11C]SMW139 standardized uptake values (SUVs) showed no statistically significant increase in the neocortex and hippocampus of TG or WT mice, which was consistent with findings from ex vivo brain autoradiography. Significantly higher [18F]F-DPA SUVs were observed in brain regions of TG compared to WT mice. Quantified P2X7-positive staining in the cortex and thalamus of TG mice showed a minor increase in receptor expression with ageing, while TSPO-positive staining in the same regions showed a more robust increase in expression in TG mice as they aged. [11C]SMW139 was rapidly metabolized in mice, with 33% of unmetabolized fraction in plasma and 29% in brain homogenates 30 min after injection. Conclusions: [11C]SMW139, which has a lower affinity for the rodent P2X7 receptor than the human version of the receptor, was unable to image the low expression of P2X7 receptor in the APP/PS1-21 mouse model. Additionally, the rapid metabolism of [11C]SMW139 in mice and the presence of several brain-penetrating radiometabolites significantly impacted the analysis of in vivo PET signal of the tracer. Finally, [18F]F-DPA targeting TSPO was more suitable for imaging reactive glia and neuroinflammatory processes in the APP/PS1-21 mouse model, based on the findings presented in this study and previous studies with this mouse model. [ABSTRACT FROM AUTHOR]

Background: Asthma is a very common respiratory disorder, affecting more than 360 million people worldwide. It is a chronic inflammatory disorder of the airways with the symptoms of shortness of breath, coughing, chest tightness, wheezing, and sometimes chest pain. Leukotrienes play an important role in bronchoconstriction during the allergen or exercise-induced acute asthma attack. Aim: The study aims to predict the interactions between leukotriene antagonist drugs and CysLT receptor-1 (CysLTR1), P2Y12 and peroxisome proliferator-activated receptor gamma (PPAR-γ) on a competitive basis. The study also has the objective of understanding the cardioprotective roles of the drugs. Introduction: Asthma is strongly linked to the development of acute coronary syndrome by the leukotriene-induced activation of CysLTR1, platelet aggregation and thrombosis by activating P2Y12. PPAR-γ is considered to show benefits against atherosclerosis, diabetes, hypertension, obesity and dyslipidaemia, which are risk factors for the development of cardiovascular disorders. Leukotriene receptor inhibitors act with these three types of receptors to show therapeutic effects. Materials and Methods: To predict the possible interactions between the drugs and the receptors, the study has used in silico methods. Results and Discussion: Montelukast, Zafirlukast and Gemilukast are potential antagonists of CysLTR1 and P2Y12. They are also responsible for the upregulation of PPAR-γ. Thus, these drugs show a cardioprotective role in asthma-induced cardiac disorders. Conclusion: A competitive in silico study of Montelukast, Zafirlukast and Gemilukast to predict their binding to CysLTR1, P2Y12 & PPAR-γ revealed that Montelukast is more effective than the other two drugs for showing a cardioprotective role. [ABSTRACT FROM AUTHOR]

Background Patients with atrial fibrillation and severe chronic kidney disease have higher risks of bleeding, thromboembolism, and mortality. However, optimal anticoagulant choice in these high‐risk patients remains unclear. Methods and Results Using deidentified electronic health records from the Optum Labs Data Warehouse, adults with atrial fibrillation and severe chronic kidney disease (estimated glomerular filtration rate

Objective: This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis. Methods: Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription-polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression. Results: Expression levels of P2Y12, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12 +/TGF-β1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues. Conclusion: Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs. [ABSTRACT FROM AUTHOR]

Background: Clopidogrel is an inhibitor of the P2Y12 platelet receptor but testing to demonstrate a drug effect is controversial since there are often discordant results between different tests methods. Methods: Samples from patients taking clopidogrel prior to intracranial flow-diversion procedures were tested using light transmission aggregometry (LTA), whole blood impedance aggregometry (WBIA) and the VerifyNow device (VND). Samples were classified as concordant if all test results were either responsive (inhibition) or resistant. Discordant results were separated using the VND into those with a responsive versus a resistant test result. Results: Samples from 96 patients were studied. Concordance for all three tests was seen in 53/96 (55%) of samples, of which 41 (43%) were responsive and 12 (12%) were resistant. Discordance was observed in 43 samples (45%), 37 (28%) of which were caused by responsive VND and either a resistant WBIA or LTA and 6 (7%) of which were caused by a resistant VND but a responsive test result using either WBIA or LTA. These two discordant groups differed in both platelet count and hematocrit, but no such difference was present between the two concordant groups. Conclusion: Discordance in P2Y12 inhibition testing may be partly explained by sample platelet count and hematocrit. [ABSTRACT FROM AUTHOR]

Pharmacological inhibition of the platelet ADP-receptor P2Y12 is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y12. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y12 inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y12 inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (<10%) of uninhibited platelets did not abrogate the antithrombotic effect of PAM to any significant extent. Finally, we demonstrate a gradual enrichment of inhibited platelets in the thrombus shell due to selective recruitment of inhibited platelets to the thrombus periphery. [ABSTRACT FROM AUTHOR]

Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. This study aimed to investigate the association between platelet miRNA levels and clopidogrel efficacy. Here we recruited 508 CAD patients who underwent clopidogrel antiplatelet therapy and determined the platelet reactivity index (PRI) to evaluate antiplatelet reactivity responses to clopidogrel. Subsequently, 22 patients with extreme clopidogrel response were selected for platelet small RNA sequencing. Another 41 CAD patients taking clopidogrel were collected to verify the differentially expressed candidate miRNAs. We found the metabolic types of the CYP2C19 enzyme (based on CYP2C19 * 2 and * 3 polymorphisms) could significantly affect the PRI of CAD patients with or without percutaneous coronary intervention (PCI) in Chinese. A total of 43 miRNAs were differentially expressed in the platelets from the 22 extreme clopidogrel response samples, and 109 miRNAs were differentially expressed in the 13 CYP2C19 extensive metabolizers with extreme clopidogrel response. Platelet miR-199a-5p levels were correlated negatively with PRI after clopidogrel therapy. Studies in cultured cells revealed that miR-199a-5p inhibited the expression of VASP, a key effector protein downstream of the P2Y12 receptor. In conclusion, we found the expression of VASP could be inhibited by miR-199a-5p, and decreased platelet miR-199a-5p was associated with high on-clopidogrel platelet reactivity in CAD patients. [ABSTRACT FROM AUTHOR]

Microglia regulate anesthesia by altering the activity of neurons in specific regions of the brain via a purinergic receptor.

General anesthesia leads to a loss of consciousness and an unrousable state in patients. Although general anesthetics are widely used in clinical practice, their underlying mechanisms remain elusive. The potential involvement of nonneuronal cells is unknown. Microglia are important immune cells in the central nervous system (CNS) that play critical roles in CNS function and dysfunction. We unintentionally observed delayed anesthesia induction and early anesthesia emergence in microglia-depleted mice. We found that microglial depletion differentially regulates neuronal activities by suppressing the neuronal network of anesthesia-activated brain regions and activating emergence-activated brain regions. Thus, microglia facilitate and stabilize the anesthesia status. This influence is not mediated by dendritic spine plasticity. Instead, it relies on the activation of microglial P2Y12 and subsequent calcium influx, which facilitates the general anesthesia response. Together, we elucidate the regulatory role of microglia in general anesthesia, extending our knowledge of how nonneuronal cells modulate neuronal activities.

Objective This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis.Methods Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription–polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression.Results Expression levels of P2Y12, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12+/TGF-β1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues.Conclusion Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs.

Pharmacological inhibition of the platelet ADP-receptor P2Y12 is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y12. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y12 inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y12 inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (

Thrombosis, or the formation of blood clots, can lead to serious medical conditions such as stroke, heart attack, and deep vein thrombosis. The purinoreceptor P2Y12 plays a critical role in the thrombotic pathway and is targeted for therapy to prevent clot formation. However, it is essential to balance the regulation of thrombosis to avoid adverse situations. This study focuses on the P2Y12 receptor and aims to discern the protein residue network and differentiate residues based on their intramolecular interactions. The study utilized a statistical analysis to characterize the significant residues involved in ligand interaction, which helps to identify critical residues that are essential for the function of the receptor. A parametric analysis of interactions of residues in the intraprotein interaction was conducted, which revealed significant residue‐based contacts that facilitate protein interactions. By examining the interactions between residues, the mechanisms underlying protein interactions were studied and the importance of specific residues in facilitating these interactions was determined. This research provides important information on P2Y12, and the findings based on the network based significance of interacting residues may contribute to the development of new therapies that target the receptor to prevent clot formation while maintaining a balance in thrombosis regulation to avoid adverse outcomes. Ultimately, this study could lead to improved treatments for thrombotic disorders and better patient outcomes. [ABSTRACT FROM AUTHOR]

Understanding the pharmacodynamic effects of platelet inhibitors is standard for developing more effective antithrombotic therapies. An example is the antithrombotic treatment of acute coronary syndrome (ACS), in particular ST-elevated myocardial infarction (STEMI) patients who are in need for rapid acting strong antithrombotic therapy despite the use of aspirin and oral P2Y12-inhibitors. In this study, we evaluated two injectable platelet inhibitors under clinical development (the P2Y12 antagonist selatogrel and the GPIIb-IIIa antagonist zalunfiban) that may be amenable to pre-hospital treatment of STEMI patients. Platelet reactivity was assessed at inhibitor concentrations that represent clinically relevant levels of platelet inhibition (IC20-50%, 1/2Cmax, and Cmax). Light transmission aggregometry (LTA), was used to evaluate the initial rate of aggregation (primary slope, PS) and maximal aggregation (MA). Both adenosine diphosphate (ADP) and thrombin receptor agonist peptide (TRAP) were used as agonists. Zalunfiban demonstrated similar inhibition of platelet aggregation when blood was collected in PPACK or TSC, whereas selatogrel demonstrated greater inhibition in PPACK. In this study, using PPACK anticoagulant, selatogrel and zalunfiban affected PS in response to ADP equivalently at all drug concentrations tested. In contrast, zalunfiban had significantly greater potency at its Cmax concentration compared to selatogrel using TRAP as agonist. Upon evaluation of MA responses at lower doses, selatogrel had greater inhibition of MA in response to ADP than zalunfiban; however, at concentrations that represent Cmax, the drugs were equivalent. Zalunfiban also had greater inhibition of MA in response to TRAP at the Cmax dose. These data suggest that zalunfiban may provide greater protection in reducing thrombus formation than selatogrel, especially since thrombin is an early, key primary agonist in the pathophysiology of thrombotic events. Key Points: Zalunfiban and selatogrel are effective inhibitors of ADP-induced platelet aggregation. Zalunfiban, compared to selatogrel, is a more potent inhibitor of TRAP-induced platelet aggregation. Zalunfiban and selatogrel pharmacodynamics should be evaluated in PPACK anticoagulant when using ADP as the agonist. Additionally, zalunfiban pharmacodynamics can also be evaluated in 3.2% TSC for MA only when using TRAP as the agonist. Zalunfiban may provide greater protection in reducing thrombus formation, since thrombin is an early agonist in the pathophysiology of thrombotic events. [ABSTRACT FROM AUTHOR]

Metastatic melanoma is a very aggressive skin cancer. Platelets are constituents of the tumor microenvironment and, when activated, contribute to cancer progression, especially metastasis and inflammation. P2Y12 is an adenosine diphosphate receptor that triggers platelet activation. Inhibition of P2Y12 by clopidogrel bisulfate (CB) decreases platelet activation, which is also controlled by the extracellular concentration and the metabolism of purines by purinergic enzymes. We evaluated the effects of CB on the viability and proliferation of cultured B16-F10 cells. We also used a metastatic melanoma model with C57BL-6 mice to evaluate cancer development and purine metabolism modulation in platelets. B16-F10 cells were administered intraperitoneally to the mice. Two days later, the animals underwent a 12-day treatment with CB (30 mg/kg by gavage). We have found that CB reduced cell viability and proliferation in B16-F10 culture in 72 h at concentrations above 30 µm. In vivo, CB decreased tumor nodule counts and lactate dehydrogenase levels and increased platelet purine metabolism. Our results showed that CB has significant effects on melanoma progression. [ABSTRACT FROM AUTHOR]

Patients with end-stage renal disease (ESRD) on maintenance dialysis have an increased risk of ischaemic events, such as recurrent myocardial infarction (MI) and stroke. Potent antiplatelet therapy may help mitigate this risk. Nonetheless, ERSD patients are also at increased risk of bleeding due to their complex vascular milieu, which limits the routine use of potent P2Y12 inhibitors. Moreover, these patients are often underrepresented or excluded from major clinical trials leaving a significant gap in existing knowledge. Understanding the mechanisms of this paradox may serve as a benchmark for the development of ESRD trials. The present review aims to provide an overview of the pathophysiological nature of increased bleeding and ischaemic risks in ERSD patients as well as summarize available evidence of antiplatelet use and propose new concepts to guide physicians in selecting appropriate drug regimes for this high-risk cohort. [ABSTRACT FROM AUTHOR]

Background: Elderly status is steadily increasing among patients with acute coronary syndrome (ACS). Dual antiplatelet therapy (DAPT) with aspirin and a potent P2Y12 receptor inhibitor is the cornerstone of treatment to prevent recurrent thrombotic complications in patients with ACS. However, DAPT in older patients is challenged by a concurrent heightened risk of ischemia and bleeding. The aim of this study is to evaluate the pharmacodynamic and pharmacokinetic profile of a lower dose of ticagrelor (60 mg twice daily) among elderly patients during the early phase of ACS. Study Design: PLINY THE ELDER (PLatelet INhibition with two different doses of potent P2y12 inhibitors in THE ELDERly population) (NCT04739384) is a prospective, randomized, open-label, crossover trial to evaluate the non-inferiority of a lower dose of ticagrelor (60 mg twice daily) compared with a standard dose (90 mg twice daily) among elderly patients with ACS undergoing percutaneous coronary intervention (PCI). A total of 50 patients, aged 75 years or more, with indication to potent P2Y12 receptor inhibitors will be randomized within 3 days from PCI for the index ACS. Patients with indication to oral anticoagulant therapy, treatment with glycoprotein IIb/IIIa inhibitors, or active bleeding will be excluded. The primary endpoint is platelet reactivity determined by P2Y12 reaction units (PRU) (VerifyNow, Accumetrics, San Diego, CA, USA) after treatment with ticagrelor 60 or 90 mg twice daily for 14 days. Secondary endpoints will include other pharmacodynamic tests of ADP-induced aggregation (light transmittance aggregometry and multiple electrode aggregometry) and determination of pharmacokinetic profile (plasma levels of ticagrelor and its metabolite AR-C124910XX) by high performance liquid chromatography-tandem mass spectrometry. Conclusions: The PLINY THE ELDER trial will determine whether a lower dose of ticagrelor confers non-inferior platelet inhibition compared with the standard dose in the early phase of ACS among elderly patients undergoing PCI, informing future clinical investigation. [ABSTRACT FROM AUTHOR]

Abstract Background Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer’s disease (AD). Tau oligomers are the most reactive species, mediating neurotoxic and inflammatory activity. Microglia are the immune cells in the central nervous system, sense the extracellular Tau via various cell surface receptors. Purinergic P2Y12 receptor can directly interact with Tau oligomers and mediates microglial chemotaxis via actin remodeling. The disease-associated microglia are associated with impaired migration and express a reduced level of P2Y12, but elevate the level of reactive oxygen species and pro-inflammatory cytokines. Results Here, we studied the formation and organization of various actin microstructures such as-podosome, filopodia and uropod in colocalization with actin nucleator protein Arp2 and scaffold protein TKS5 in Tau-induced microglia by fluorescence microscopy. Further, the relevance of P2Y12 signaling either by activation or blockage was studied in terms of actin structure formations and Tau deposits degradation by N9 microglia. Extracellular Tau oligomers facilitate the microglial migration via Arp2-associated podosome and filopodia formation through the involvement of P2Y12 signaling. Similarly, Tau oligomers induce the TKS5-associated podosome clustering in microglial lamella in a time-dependent manner. Moreover, the P2Y12 was evidenced to localize with F-actin-rich podosome and filopodia during Tau-deposit degradation. The blockage of P2Y12 signaling resulted in decreased microglial migration and Tau-deposit degradation. Conclusions The P2Y12 signaling mediate the formation of migratory actin structures like- podosome and filopodia to exhibit chemotaxis and degrade Tau deposit. These beneficial roles of P2Y12 in microglial chemotaxis, actin network remodeling and Tau clearance can be intervened as a therapeutic target in AD.

Rakhmad Hidayat,1– 3 Al Rasyid,2,3 Salim Harris,2,3 Alida Harahap,2 Herqutanto,2 Melva Louisa,2 Erlin Listiyaningsih,4 Aldy Safruddin Rambe,5 Tonny Loho6 1Doctoral Program in Medical Sciences Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia; 2Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia; 3Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 4Harapan Kita Hospital, Jakarta, Indonesia; 5Sumatera Utara University, Medan, Indonesia; 6Faculty of Medicine and Health Science, Kristen Krida Wacana University, Jakarta, IndonesiaCorrespondence: Rakhmad Hidayat, Tel +62 813 88756299, Email rhidayat.md@gmail.comBackground: Stroke is one of the highest causes of disability and mortality in several countries worldwide. Secondary prevention is important in the management of stroke. Clopidogrel is widely used in Asia as secondary prevention for ischemic stroke, even though several studies in Western show limited data related to clopidogrel resistance in Asia. This study aims to determine the correlation between P2Y12 genetic polymorphism and clopidogrel resistance in Indonesia.Methods: This study was conducted on one-year duration, the subjects were chosen through the consecutive sampling method, all subjects were examined for genetics and resistance to clopidogrel. The data were analyzed through statistical analysis, a bivariate analysis was conducted to determine the correlation between several variables and the resistance variable. This study employed resistance diagnostic methods with VerifyNow. Polymorphism of receptor P2Y12 was tested with the Polymerase Chain Reaction method (PCR) and analysis of restriction fragment length polymorphism (RFLP). The genes tested in this study were G52T and C34T.Results: The number of participants in this study was 112. Examination of gene P2Y12 showed that the majority was homozygote, wild-type C34T allele (67%), and G52T (66.1%). There was no significant correlation between clopidogrel resistance and gene G52T and C34T of P2Y12 (p > 0.05). Hb levels significantly correlated with P2Y12 G52T (p = 0.024). Meanwhile, Fatty Liver significantly correlated with P2Y12 C34T (p = 0.037).Conclusion: Indonesia showed a low clopidogrel resistance rate and a very low C34T and G52T allele P2Y12 gene mutation, meaning that Indonesia had low mutations in the P2Y12. This is the cause of clopidogrel resistance in this study only 15%. Therefore, in a region with less clopidogrel resistance, examination of the P2Y12 gene would not give significant results.Keywords: clopidogrel resistance, P2Y12, stroke, antiplatelet

Abstract Backgrounds Remarkable interindividual variability in clopidogrel response is observed, genetic polymorphisms in P2RY12 and its signal pathway is supposed to affect clopidogrel response in CHD patients. Methods 539 CHD patients treated with clopidogrel were recruited. The platelet reaction index (PRI) indicated by VASP-P level were detected in 12–24 h after clopidogrel loading dose or within 5–7 days after initiation of maintain dose clopidogrel. A total of 13 SNPs in relevant genes were genotyped in sample A (239 CHD patients). The SNPs which have significant differences in PRI will be validated in another sample (sample B, 300 CHD patients). Results CYP2C19*2 increased the risk of clopidogrel resistance significantly. When CYP2C19*2 and CYP2C19*3 were considered, CYP2C19 loss of function (LOF) alleles were associated with more obviously increased the risk of clopidogrel resistance; P2RY12 rs6809699C > A polymorphism was also associated with increased risk of clopidogrel resistance (AA vs CC: P = 0.0398). This difference still existed after stratification by CYP2C19 genotypes. It was also validated in sample B. The association was also still significant even in the case of stratification by CYP2C19 genotypes in all patients (sample A + B). Conclusion Our data suggest that P2RY12 rs6809699 is associated with clopidogrel resistance in CHD patients. Meanwhile, the rs6809699 AA genotype can increase on-treatment platelet activity independent of CYP2C19 LOF polymorphisms.

Background: Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer's disease (AD). Tau oligomers are the most reactive species, mediating neurotoxic and inflammatory activity. Microglia are the immune cells in the central nervous system, sense the extracellular Tau via various cell surface receptors. Purinergic P2Y12 receptor can directly interact with Tau oligomers and mediates microglial chemotaxis via actin remodeling. The disease-associated microglia are associated with impaired migration and express a reduced level of P2Y12, but elevate the level of reactive oxygen species and pro-inflammatory cytokines. Results: Here, we studied the formation and organization of various actin microstructures such as-podosome, filopodia and uropod in colocalization with actin nucleator protein Arp2 and scaffold protein TKS5 in Tau-induced microglia by fluorescence microscopy. Further, the relevance of P2Y12 signaling either by activation or blockage was studied in terms of actin structure formations and Tau deposits degradation by N9 microglia. Extracellular Tau oligomers facilitate the microglial migration via Arp2-associated podosome and filopodia formation through the involvement of P2Y12 signaling. Similarly, Tau oligomers induce the TKS5-associated podosome clustering in microglial lamella in a time-dependent manner. Moreover, the P2Y12 was evidenced to localize with F-actin-rich podosome and filopodia during Tau-deposit degradation. The blockage of P2Y12 signaling resulted in decreased microglial migration and Tau-deposit degradation. Conclusions: The P2Y12 signaling mediate the formation of migratory actin structures like- podosome and filopodia to exhibit chemotaxis and degrade Tau deposit. These beneficial roles of P2Y12 in microglial chemotaxis, actin network remodeling and Tau clearance can be intervened as a therapeutic target in AD. [ABSTRACT FROM AUTHOR]

The P2Y12 receptor is an important member of the purinergic receptor family, known for its critical role in platelet activation and thrombosis. In our previously published study, the acridinone analogue NSC618159 was identified as a potent antagonist of P2Y12. In this work, we investigate the conformational changes in P2Y12 when bound to NSC618159 using molecular dynamics simulations on the receptor's active and inactive forms (4PXZ and 4NTJ, respectively). It was observed that it took the systems about 7 ns and 12 ns to stabilise when NSC618159 was in complex with the active and inactive forms of P2Y12, respectively. Additionally, the binding pocket of the crystal structure 4PXZ expanded from 172.34 Å3 to an average of 661.55 Å3 when bound to NSC618159, with a maximum pocket volume of 820.49 Å3. This expansion was attributed to the pulled away transmembrane (TM) helices and the adoption of a more open conformation by extracellular loop 2 (EL2). In contrast, 4NTJ's pocket volume was mostly consistent and had an average of 1203.82 Å3. Moreover, the RMSF profile of the NSC618159-4PXZ complex showed that residues of TM-I and TM-VII had similar fluctuations to the 4NTJ crystal structure, representing the inactive form of P2Y12. Finally, the energy components and binding affinities of NSC618159 towards the active and inactive forms of P2Y12 were predicted using the MM-PBSA approach. According to the results, the binding affinity of NSC618159 towards both active (4PXZ) and inactive (4NTJ) forms of P2Y12 was found to be almost identical, with values of −43.52 and −41.68 kcal/mol, respectively. In conclusion, our findings provide new insights into the conformational changes of P2Y12 upon binding to NSC618159 and may have implications for the development of new P2Y12 antagonists with enhanced potency and specificity. [ABSTRACT FROM AUTHOR]

People living with HIV (PLWHIV) present an increased risk of adverse cardiovascular events. We aimed to assess whether antiretroviral therapy (ART) pharmacologically enhances platelet reactivity and platelet activation intensity, and explore the potential association with underlying inflammatory status. This was a cross-sectional cohort study carried out among PLWHIV on diverse ART regimens. Platelet reactivity and activation intensity were assessed using the bedside point-of-care VerifyNow assay, in P2Y12 reaction units (PRU), measurements of monocyte-platelet complexes, and P-selectin and GPIIb/IIIa expression increase, following activation with ADP, respectively. Levels of major inflammatory markers and whole blood parameters were also evaluated. In total, 71 PLWHIV, 59 on ART and 22 healthy controls, were included in this study. PRU values were significantly elevated in PLWHIV compared to controls [Mean; 257.85 vs. 196.67, p < 0.0001], but no significant differences were noted between ART-naïve or ART-experienced PLWHIV, or between TAF/TDF and ABC based regimens, similar to systemic inflammatory response. However, within-group analysis showed that PRUs were significantly higher in ABC/PI vs ABC/INSTI or TAF/TDF + PI patients, in line with levels of IL-2. PRU values did not correlate strongly with CD4 counts, viral load, or cytokine values. P-selectin and GPIIb/IIIa expression increased following ADP activation and were significantly more prominent in PLWHIV (p < 0.005). Platelet reactivity and platelet activation intensity were shown to be increased in PLWHIV, but they did not appear to be related to ART initiation, similar to the underlying systemic inflammatory response. [ABSTRACT FROM AUTHOR]

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BackgroundDual antiplatelet therapy (DAT), most commonly with aspirin and Clopidogrel, is the standard of care for intracranial stenting, including flow diversion. Clopidogrel response varies by individual.ObjectiveTo investigate the real-world precision of VerifyNow P2Y12 assessment (Accumetrics, San Diego, California) of Clopidogrel response.MethodsUsing a prospectively-collected, IRB-approved cerebral aneurysm database 643 patients were identified who were treated with the Pipeline embolization device from 2011 to 2017. Patients with multiple P2Y12 assays drawn within a 24-h window were identified. A single patient could contribute multiple, independent sets. Levels drawn before a 5-d course of DAT and patients who received alternative antiplatelet agents were excluded. Therapeutic range was defined as platelet reaction units (PRU) 60-200.ResultsA total of 1586 P2Y12 measurements were recorded; 293 (46%) patients had more than one assay. One hundred forty (22%) patients had multiple P2Y12 measurements within 24 h. These patients accounted for 230 independent 24-h sets. The average P2Y12 fluctuation across all sets was 35 points; the 25th, 50th, and 75th percentiles were 12, 26, and 48 points, respectively. Of the 230 24-h sets of P2Y12 assays, 76% remained within their original therapeutic category: 100 (43%) all therapeutic, 54 (23%) all hypo-responsive, and 21 (9%) all hyper-responsive. Twenty-four percent of patients fluctuated between therapeutic categories when multiple P2Y12 assessments were drawn within a 24-h period: 29 (13%) between hypo-response and therapeutic, 23 (10%) between hyper-response and therapeutic, and 3 (1%) between hypo-response and hyper-response.ConclusionOur experience suggests P2Y12 is an often-imprecise measure, and this should be considered when utilizing P2Y12 levels for clinical decisions.

In addition to the key role in hemostasis and thrombosis, platelets have also been wildly acknowledged as immune regulatory cells and involving in the pathogenesis of inflammation-related diseases. Since purine receptor P2Y12 plays a crucial role in platelet activation, P2Y12 antagonists such as clopidogrel, prasugrel, and ticagrelor have been widely used in cardiovascular diseases worldwide in recent decades due to their potent antiplatelet and antithrombotic effects. Meanwhile, the role of P2Y12 in inflammatory diseases has also been extensively studied. Relatively, there are few studies on the regulation of P2Y12. This review first summarizes the various roles of P2Y12 in the process of platelet activation, as well as downstream effects and signaling pathways; then introduces the effects of P2Y12 in inflammatory diseases such as sepsis, atherosclerosis, cancer, autoimmune diseases, and asthma; and finally reviews the current researches on P2Y12 regulation. [ABSTRACT FROM AUTHOR]

Objectives: "Clopidogrel resistance," also defined as heightened platelet reactivity (HPR) while on clopidogrel therapy, may lead to a sub-optimal antiplatelet effect and a potential thrombotic event. There is limited literature addressing the prevalence of HPR in a large cohort of patients receiving either coronary or endovascular interventions. Methods: In a large integrated healthcare system, patients with a P2Y12 reaction units (PRU) test were identified. HPR was defined as a PRU ≥ 200 during clopidogrel therapy. Vascular and coronary interventions were identified utilizing CPT codes, HPR prevalence was calculated, and Fischer's exact test was used to determine significance. Results: From an initial cohort of 2,405,957 patients (October 2014 to January 2020), we identified 3301 patients with PRU tests administered. Of these, 1789 tests had a PRU ≥ 200 (HPR overall prevalence, 54%). We then identified 1195 patients who underwent either an endovascular or coronary procedure and had a PRU measurement. This corresponded to 935 coronary and 260 endovascular interventions. In the coronary cohort, the HPR prevalence was 54% (503/935). In the vascular cohort, the HPR prevalence was 53% (137/260); there was no difference between cohorts in HPR prevalence (p = 0.78). Conclusion: "Clopidogrel resistance" or HPR was found to be present in nearly half of patients with cardiovascular disease undergoing intervention. Our data suggest HPR is more common in the cardiovascular patient population than previously appreciated. Evaluating patients for HPR is both inexpensive ($25) and rapid (< 10 min). Future randomized studies are warranted to determine whether HPR has a clinically detectable effect on revascularization outcomes. [ABSTRACT FROM AUTHOR]

Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. This study aimed to investigate the association between platelet miRNA levels and clopidogrel efficacy. Here we recruited 508 CAD patients who underwent clopidogrel antiplatelet therapy and determined the platelet reactivity index (PRI) to evaluate antiplatelet reactivity responses to clopidogrel. Subsequently, 22 patients with extreme clopidogrel response were selected for platelet small RNA sequencing. Another 41 CAD patients taking clopidogrel were collected to verify the differentially expressed candidate miRNAs. We found the metabolic types of the CYP2C19 enzyme (based on CYP2C19 * 2 and * 3 polymorphisms) could significantly affect the PRI of CAD patients with or without percutaneous coronary intervention (PCI) in Chinese. A total of 43 miRNAs were differentially expressed in the platelets from the 22 extreme clopidogrel response samples, and 109 miRNAs were differentially expressed in the 13 CYP2C19 extensive metabolizers with extreme clopidogrel response. Platelet miR-199a-5p levels were correlated negatively with PRI after clopidogrel therapy. Studies in cultured cells revealed that miR-199a-5p inhibited the expression of VASP, a key effector protein downstream of the P2Y12 receptor. In conclusion, we found the expression of VASP could be inhibited by miR-199a-5p, and decreased platelet miR-199a-5p was associated with high on-clopidogrel platelet reactivity in CAD patients. What is the context? ● Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. ● Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. ● Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. What is new? ● We found that decreased platelet miR-199a-5p level was associated with high on-clopidogrel platelet reactivity. ● Overexpression of miR-199a-5p significantly down-regulated the expression of VASP protein in cultured cells. What is the impact? ● The current study provided new insights into the exploration of interindividual variability in clopidogrel response from the perspective of miR-199a-5p and VASP interaction. [ABSTRACT FROM AUTHOR]

OBJECTIVE Systemic-to-pulmonary artery shunts are amongst the most common palliative procedures performed in neonates with congenital heart defects. These procedures require immediate postoperative thromboprophylaxis to prevent life-threatening shunt thrombosis. The novel use of intravenous P2Y12 platelet receptor antagonists has led to a need for dosing recommendations and monitoring. This study aims to determine cangrelor dosing in neonates through laboratory assessment of P2Y12 receptor reactivity and adverse events. METHODS Observational retrospective cohort study on the use of cangrelor for thromboprophylaxis in the immediate postoperative period of neonates undergoing placement of systemic-to-pulmonary artery shunts in a tertiary children's hospital from March 2020 to March 2021. RESULTS Ten neonates receiving cangrelor post systemic-to-pulmonary artery shunt placement were included in the study. Median age and weight were 4 days (IQR, 2.75-5.25) and 3.49 kg (IQR, 3.1-3.75), respectively. Five (50%) patients received a 3.5-mm shunt, while the remaining patients received a 4-mm shunt. For thrombin inhibition, 5 (50%) patients received heparin and 5 (50%) received bivalirudin. Median cangrelor dose was 0.1 mcg/kg/min (IQR, 0.1-0.1). Median achieved P2Y12 reaction units (PRU) at this cangrelor dose was 127.5 (IQR, 72.5-173.75). No shunt thrombosis occurred in these patients; however, there was 1 minor hemorrhagic event. CONCLUSIONS Our study suggests that a cangrelor dose of 0.1 mcg/kg/min is associated with therapeutic PRU and prevents shunt thrombosis in neonates post systemic-to-pulmonary artery shunt, with minimal hemorrhagic complications. ABBREVIATIONS ADP, adenosine diphosphate; CICU, cardiac intensive care unit; ECMO, extracorporeal membrane oxygenation; FFP, fresh frozen plasma; HLHS, hypoplastic left heart syndrome; IQR, interquartile range; PRBC, packed red blood cells; PRU, P2Y12 reaction units; PTT, partial thromboplastin time; S-PA, systemic-to-pulmonary artery; VAD, ventricular assist device [ABSTRACT FROM AUTHOR]

Abstract Background High on-treatment platelet reactivity (HTPR) remains a major problem in the acute management of ST-elevation myocardial infarction (STEMI), leading to higher rates of stent thrombosis and mortality. We aimed to investigate a novel, prehospital treatment strategy using cangrelor and tested its pharmacodynamic effects in a model using healthy volunteers. Methods We conducted a dose-finding, open-label, pilot trial including 12 healthy volunteers and tested three ascending bolus infusions of cangrelor (5 mg, 10 mg and 20 mg) and a bolus infusion followed by a continuous infusion via an intravenous (IV) flow regulator. Platelet function was assessed using multiple electrode aggregometry (MEA), vasodilator-stimulated phosphoprotein phosphorylation assay (VASP-P) and the platelet function analyzer. In an ex vivo experiment, epinephrine was used to counteract the antiplatelet effect of cangrelor. Results All cangrelor bolus infusions resulted in immediate and pronounced platelet inhibition. Bolus infusions of cangrelor 20 mg resulted in sufficient platelet inhibition assessed by MEA for 20 min in 90% of subjects. Infusion of cangrelor via the IV flow regulator resulted in sufficient platelet inhibition throughout the course of administration. Ex vivo epinephrine, in concentrations of 200 and 500 ng/mL was able to partially reverse the antiplatelet effect of cangrelor in a dose-dependent manner. Conclusions Weight-adapted bolus infusions followed by a continuous infusion of cangrelor via IV flow regulator result in immediate and pronounced platelet inhibition in healthy subjects. Cangrelor given as weight-adapted bolus infusion followed by a continuous infusion using an IV flow regulator may be a viable treatment approach for effective and well controllable prehospital platelet inhibition. Trial registration EC (Medical University of Vienna) 1835/2019 and EudraCT 2019-002792-34 .

Microglia activation after spinal cord injury (SCI) is a double-edged sword, modulation of the activated microglia populations toward pro-regenerative phenotypes highlights the potential therapeutic implications. P2Y12, a microglia-specific marker, remains underexplored in its capacity to polarize microglial activation populations in SCI repair. We aimed to explore the effects of modulating P2Y12 on microglia function after spinal cord injury, and further on axonal regeneration and motor recovery after spinal cord injury. The study employed both in vitro and in vivo models, using BV2 cells and a mouse model of SCI, respectively. Ticagrelor, a P2Y12 antagonist, was administered via a collagen scaffold to ensure stable and sustained release. Transcriptome sequencing analysis, immunofluorescence staining, and Basso Mouse Scale (BMS) scores were used to assess microglial activation, axonal regeneration, and functional recovery. Herein, we observed P2Y12+ microglia localized predominantly at the lesion periphery within 3 days post injury (dpi), manifesting a pro-inflammatory phenotype, but not anti-inflammatory phenotype. In vitro investigations revealed that P2Y12 inhibition of the activated microglia curtailed pro-inflammatory differentiation while augmenting anti-inflammatory differentiation. Leveraging this insight, we engineered a collagen scaffold-based delivery system for sustained release of the P2Y12 antagonist, ticagrelor, at the injury site in a mouse complete SCI model. Notably, P2Y12 suppression markedly enhanced axonal regeneration within the injured site and ameliorated lower limb motor functions in SCI mice. Collectively, our findings illuminate P2Y12-targeted microglial modulation as a promising therapeutic approach for SCI. [Display omitted] [ABSTRACT FROM AUTHOR]

Hypertension is usually accompanied by elevated sympathetic tonicity, but how sympathetic hyperactivity is triggered is not clear. Recent advances revealed that microglia-centered neuroinflammation contributes to sympathetic excitation in hypertension. In this study, we performed a temporospatial analysis of microglia at both morphological and transcriptomic levels and found that microglia in the hypothalamic paraventricular nucleus (PVN), a sympathetic center, were early responders to hypertensive challenges. Vasculature analyses revealed that the PVN was characterized by high capillary density, thin vessel diameter, and complex vascular topology relative to other brain regions. As such, the PVN was susceptible to the penetration of ATP released from the vasculature in response to hemodynamic disturbance after blood pressure increase. Mechanistically, ATP ligation to microglial P2Y 12 receptor was responsible for microglial inflammatory activation and the eventual sympathetic overflow. Together, these findings identified a distinct vasculature pattern rendering vulnerability of PVN pre-sympathetic neurons to hypertension-associated microglia-mediated inflammatory insults. [Display omitted] • Early occurrence of microgliosis in the PVN is a hallmark of murine hypertension models • Distinct vasculature topology makes an easy entry of blood-borne ATP to the PVN • ATP-P2Y 12 -C/EBPβ pathway stimulates PVN microglia and eventually sympathetic activities • Disruption of ATP-P2Y 12 -C/EBPβ pathway in the PVN could limit hypertension development Sympathetic over-excitation could take place as a secondary factor contributing to hypertension. However, the mechanisms underlying sympathetic flare-up during hypertension are unclear. Wei et al. find that due to a distinct vasculature organization in the hypothalamic paraventricular nucleus, blood-borne ATP preferentially infiltrates into this nucleus during hypertension. Elevated ATP stimulates local microglia via the P2Y 12 receptor, which drives sympathetic hypertonicity. [ABSTRACT FROM AUTHOR]

Ischemic events are associated with severe inflammation and are here referred to as ischemic inflammatory response (IIR). Recent studies identified the formation of platelet–neutrophil complexes (PNC) as key players in IIR. We investigated the role of extracellular platelet nucleotide signaling in the context of IIR and defined a cybernetic circle, including description of feedback loops. Cybernetic circles seek to integrate different levels of information to understand how biological systems function. Our study specifies the components of the cybernetic system of platelets in IIR and describes the theoretical progression of IIR passing the cybernetic cycle with positive and negative feedback loops based on nucleotide-dependent signaling and functional regulation. The cybernetic components and feedback loops were explored by cytometry, immunohistological staining, functional blocking antibodies, and ADP/ATP measurements. Using several ex vivo and in vivo approaches we confirmed cybernetic parameters, such as controller, sensor, and effector (VASP phosphorylation, P2Y12, ADORAs and GPIIb/IIIa activity), as well as set points (ADP, adenosine) and interfering control and disturbance variables (ischemia). We demonstrate the impact of the regulated platelet–neutrophil complex (PNC) formation in blood and the resulting damage to the affected inflamed tissue. Taken together, extracellular nucleotide signaling, PNC formation, and tissue damage in IIR can be integrated in a controlled cybernetic circle of platelet function, as introduced through this study. [ABSTRACT FROM AUTHOR]

Background and Aim of the Study: Antiplatelet drugs available on the market have multiple side effects and pose drug interactions, which actuated the researchers to consider better alternatives by using plant extracts. It is well known that medicinal plants possessing anti-inflammatory action usually have antiplatelet aggregation and anticoagulation potential. Therefore, it was hypothesized that resins of Astragalus sarcocolla Dymock possessing anti-inflammatory properties would also manifest antiplatelet aggregation and anticoagulant properties. The objective of the present study was to assess the antiplatelet and anticoagulant effects of four different concentrations of ethanolic extracts (100, 80, 60, and 40%) of A. sarcocolla Dymock. Materials and Methods: Four different doses of A. sarcocolla Dymock extract (2.5, 5, 7.5, and 10 μg) were prepared for assays. In vitro antiplatelet and anticoagulant effects using human blood were studied in 42 healthy males aged between 25 and 35 years. Aspirin (0.5 μg) was used as the positive control for the antiplatelet aggregation assay. Furthermore, molecular docking was done to check the interaction between plant constituents and P2Y1, P2Y12, and phosphoinositide 3-kinase (PI3K). Chlorogenic acid, ferulic acid, and cinnamic acid were quantified using high-performance liquid chromatography (HPLC)-UV in ethanolic extract. Results: An HPLC analysis of the ethanolic extract of A. sarcocolla Dymock revealed the presence of chlorogenic acid, ferulic acid, and cinnamic acid. All the extracts of A. sarcocolla Dymock significantly inhibited aggregation of platelets against all three agonists' epinephrine (EPI), adenosine 5' diphosphate (ADP), and collagen (COL) in a concentration-dependent manner. All the extracts significantly affected prothrombin time and activated partial thromboplastin time in a concentration-dependent manner. Molecular docking showed strong interactions of chlorogenic acid and ferulic acid with P2Y1, P2Y12, and PI3K. Conclusion: The data of the present study revealed the inhibition of platelet aggregation and anticoagulation potential of active compounds of Astragalus sarcocolla Dymock, together with their significant interaction profile with the selected therapeutic targets. [ABSTRACT FROM AUTHOR]

Platelets play a key role in arterial thrombosis and antiplatelet therapy is pivotal in the treatment of cardiovascular disease. Current antiplatelet drugs target different pathways of platelet activation and show specific pharmacodynamic and pharmacokinetic characteristics, implicating clinically relevant drug–drug interactions. This article reviews the role of platelets in hemostasis and cardiovascular thrombosis, and discusses the key pharmacodynamics, drug–drug interactions and reversal strategies of clinically used antiplatelet drugs. Antiplatelet therapies target distinct pathways of platelet activation: thromboxane A2 synthesis, adenosine diphosphate-mediated signaling, integrin αIIbβ3 (GPIIb/IIIa), thrombin-mediated platelet activation via the PAR1 receptor and phosphodiesterases. Key clinical drug–drug interactions of antiplatelet agents involve acetylsalicylic acid – ibuprofen, clopidogrel – omeprazole, and morphine – oral P2Y12 inhibitors, all of which lead to an attenuated antiplatelet effect. Platelet function and genetic testing and the use of scores (ARC-HBR, PRECISE-DAPT, ESC ischemic risk definition) may contribute to a more tailored antiplatelet therapy. High on-treatment platelet reactivity presents a key problem in the acute management of ST-elevation myocardial infarction (STEMI). A treatment strategy involving early initiation of an intravenous antiplatelet agent may be able to bridge the gap of insufficient platelet inhibition in high ischemic risk patients with STEMI. [ABSTRACT FROM AUTHOR]

Clopidogrel is a widely prescribed prodrug with anti-thrombotic activity through irreversible inhibition of the P2Y12 receptor on platelets. It is FDA-approved for the clinical management of thrombotic diseases like unstable angina, myocardial infarction, stroke, and during percutaneous coronary interventions. Hepatic clopidogrel metabolism generates several distinct metabolites. Only one of these metabolites is responsible for inhibiting the platelet P2Y12 receptor. Importantly, various non-hemostatic effects of clopidogrel therapy have been described. These non-hemostatic effects are perhaps unsurprising, as P2Y12 receptor expression has been reported in multiple tissues, including osteoblasts, leukocytes, as well as vascular endothelium and smooth muscle. While the "inactive" metabolites have been commonly thought to be biologically inert, recent findings have uncovered P2Y12 receptor-independent effects of clopidogrel treatment that may be mediated by understudied metabolites. In this review, we summarize both the P2Y12 receptor-mediated and non-P2Y12 receptor-mediated effects of clopidogrel and its metabolites in various tissues. [ABSTRACT FROM AUTHOR]

Aims: Although dual antiplatelet therapy with aspirin and a potent P2Y12 receptor inhibitor is currently recommended in patients with acute coronary syndrome (ACS), its use in elderly patients remains challenging. The aim of this trial is to evaluate the pharmacodynamic and pharmacokinetic profile of ticagrelor 60 vs. 90 mg twice daily among elderly patients (≥75 years) with ACS undergoing percutaneous coronary intervention (PCI)., Methods and Results: PLINY The ELDER (NCT04739384) was a randomized, crossover trial testing the non-inferiority of a lower vs. standard dose of ticagrelor with respect to the primary endpoint of P2Y12 inhibition as determined by pre-dose P2Y12 reaction units (PRU) using the VerifyNow-P2Y12 (Accumetrics, San Diego, CA, USA). Other pharmacodynamic tests included light transmittance aggregometry, multiple electrode aggregometry, and response to aspirin. Plasma levels of ticagrelor and its active metabolite AR-C124910XX were also evaluated. A total of 50 patients (mean age 79.6 ± 4.0 years, females 44%) were included in the trial. Ticagrelor 60 mg was non-inferior to ticagrelor 90 mg according to VerifyNow-P2Y12 results (PRU 26.4 ± 32.1 vs. 30.4 ± 39.0; least squares mean difference: -4; 95% confidence interval: -16.27 to 8.06; P for non-inferiority = 0.002). Other pharmacodynamic parameters were similar between the two ticagrelor doses and there were no differences in response to aspirin. Plasma levels of ticagrelor (398.29 ± 312.36 ng/mL vs. 579.57 ± 351.73 ng/mL, P = 0.006) and its active metabolite were significantly lower during treatment with ticagrelor 60 mg., Conclusion: Although plasma concentrations were lower, ticagrelor 60 mg twice daily provided a similar magnitude of platelet inhibition compared with ticagrelor 90 mg twice daily among elderly patients undergoing PCI., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background and Purpose: Although the amphiphilic nature of the widely used antithrombotic drug Ticagrelor is well known, it was never considered as a membranotropic agent capable of interacting with the lipid bilayer in a receptor-independent way. In this study, we investigated the influence of Ticagrelor on plasma membrane lipid order in platelets and if this modulates the potency of Ticagrelor at the P2Y 12 receptor., Experimental Approach: We combined fluorescent in situ, in vitro and in silico approaches to probe the interactions between the plasma membrane of platelets and Ticagrelor. The influence of Ticagrelor on the lipid order of the platelet plasma membrane and large unilamellar vesicles was studied using the advanced fluorescent probe NR12S. Furthermore, the properties of model lipid bilayers in the presence of Ticagrelor were characterized by molecular dynamics simulations. Finally, the influence of an increased lipid order on the dose-response of platelets to Ticagrelor was studied., Key Results: Ticagrelor incorporates spontaneously into lipid bilayers and affects the lipid order of the membranes of model vesicles and isolated platelets, in a nontrivial composition and concentration-dependent manner. We showed that higher plasma membrane lipid order in platelets leads to a lower IC 50 value for Ticagrelor. It is shown that membrane incorporation of Ticagrelor increases its potency at the P2Y 12 receptor, by increasing the order of the platelet plasma membrane., Conclusion and Implications: A novel dual mechanism of Ticagrelor action is suggested that combines direct binding to P2Y 12 receptor with simultaneous modulation of receptor-lipid microenvironment., (© 2024 British Pharmacological Society.)

Background: Clopidogrel is the most frequently used P2Y12 inhibitor as a component of the dual antiplatelet regimen in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Prior studies have shown the variable efficacy of clopidogrel due to genotypic differences in the CYP2C19 enzyme function, which converts clopidogrel to its active metabolite. The aim of this meta-analysis is to evaluate the effectiveness of genotype testing-guided P2Y12 inhibitor prescription therapy to patients after PCI for ACS compared to non-genotype guided conventional treatment.Methods: A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify relevant trials. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints.Results: Seven studies with 9617 patients were included. Genotype-guided strategy arm included prasugrel or ticagrelor prescription to patients with loss of function (LOF) of CYP219 alleles (most commonly alleles being *2 and *3) and clopidogrel prescription to those without the LOF allele. The conventional arm included patients treated with clopidogrel without genotype testing. Comparison of genotype arm with conventional arm showed decreased major adverse cardiovascular events (MACE), improved cardiovascular (CV) mortality, and reduced incidence of myocardial infarction (MI) in the genotype arm, and a similar stroke incidence in the two arms. Regarding adverse events, the incidence of stent thrombosis was lower in the genotype arm than the conventional arm.Conclusion: Our analysis illustrates the possible advantages of genotype-guided P2Y12 inhibitor prescription strategy compared to non-genotype-guided strategy with reductions in MACE, CV mortality, MI, and stent thrombosis. This analysis can be used as a stepping stone to conducting further trials determining the efficacy of this treatment strategy in various ACS subtypes. [ABSTRACT FROM AUTHOR]

Lumbar facet osteoarthritis (FJOA) is a major cause of severe lower back pain and disability worldwide. However, the mechanism underlying cartilage degeneration in FJOA remains unclear. The purpose of this study was to investigate the regulation and mechanism of P2Y12 on chondrocyte apoptosis in FJOA. The experimental rats were randomly divided into non-operation (n = 20) and operation groups (n = 20). In the operation group, Sodium iodoacetate (MIA, Sigma, 200 mg/mL) was injected into the right L4/5 facet process using a blunt nanoneedle 26 (WPI, Sarasota, FL, USA) under the control of an injection pump. The final injection volume was 5µL and the injection rate was 2µL/min. The facet joint was removed four weeks after surgery. After the operation, samples were stored at -80 °C until further use, whereby the right facet joints in each group were tested. Hematoxylin and eosin (HE) and iron-red solid green staining were used to observe the degeneration of articular chondrocytes in rats. Immunohistochemistry and western blotting were used to observe the expressions of P2Y12, Matrix metalloproteinase 13 (MMP13), Collagen II (COL2), and other cartilage degeneration and apoptosis-related genes. Co-localization of P2Y12-cleaved caspase-3 in the apoptosis model was detected by dual-standard immunofluorescence staining. Apoptosis was also detected by flow cytometry and TUNEL assay.P2Y12 is highly expressed in OA cartilage tissue, and inhibits IL-1β -induced chondrocyte apoptosis through PI3K/AKT signaling pathway, thus playing a certain protective role on cartilage. [ABSTRACT FROM AUTHOR]

目的二磷酸腺苷受体P2Y12介导的血小板活化是血小板活化及血栓形成的核心机制，本研究探讨囊性纤维化跨膜转导调节子（CFTR）对P2Y12介导的血小板活化的影响。方法应用8~16周龄CFTR全基因敲除（Cftr-/-）小鼠及野生型（Cftr+/+）小鼠，分别制备胶原蛋白和肾上腺素诱导的肺栓塞小鼠模型。分离Cftr-/-和Cftr+/+小鼠外周血的血小板， 采用免疫印迹技术检测P2Y12、PI3K以及AKT 总蛋白及磷酸化蛋白的表达。采用二磷酸腺苷（ADP）孵育人巨核细胞株Meg-01，检测ADP对CFTR和上述蛋白表达的影响。进一步应用特异性CFTR氯通道抑制剂CFTRinh-172与Meg-01细胞共孵育，检测其对CFTR和上述蛋白表达的影响。结果与Cftr+/+小鼠肺栓塞模型组相比，Cftr-/-鼠肺栓塞组织切片栓塞显著增加。Cftr-/-显著增加小鼠外周血血小板P2Y12、磷酸化PI3K和AKT 蛋白表达。P2Y12全基因敲除小鼠血小板CFTR蛋白表达无明显改变，上述结果提示CFTR负性调控P2Y12维持正常血小板活化功能。Meg-01细胞实验结果表明 ADP浓度依赖性地诱导Meg-01细胞P2Y12蛋白和PI3K以及AKT蛋白磷酸化增高，而CFTR蛋白表达水平逐渐降低。CFTR 特异性阻断剂CFTRinh-172显著诱导Meg-01细胞P2Y12蛋白表达增高。结论本研究揭示了血小板活化的一个新机制，即CFTR通过调控血小板P2Y12蛋白表达影响血小板活化。

Xiao Zhang,1,&ast; Juntao Wang,1,&ast; Aihua Sui,2 Nannan Zhang,1 Qiulan Lv,2 Zhenfang Liu3 1Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China; 2Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China; 3Department of Emergency, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhenfang Liu Email liuzhenfangzf@outlook.comBackground and Objective: Neuropathic pain remains a clinical challenge with limited effective treatments. Previous studies have found that magnolol (Mag), an ingredient existing in some herbs, showed neuroprotective effect. However, it remains unclear whether Mag can alleviate neuropathic pain.Methods: Chronic constriction injury (CCI) is used as the neuropathic pain model. Mice were randomly divided into 5 groups: Sham, CCI, CCI + 5, 10, 30 mg/kg Mag groups. Thermal and mechanical paw withdrawal threshold were performed at baseline and on the 3rd, 5th, 7th, 14th days post-surgery. Lumbar spinal cord and blood samples were collected on the 14th day. Blood lipid profile, kidney and liver functions, as well as the activation of microglia were evaluated, along with the related signal pathway examined using multiple methods including immunohistochemistry, RT-PCR and Western blot.Results: Mag alleviated thermal and mechanical hypersensitivity in CCI mice. CCI activated microglia and upregulated the expression of P2Y12, while Mag inhibited microglial activation, and downregulated the expression of P2Y12. Mag also blocked the activation of p38 mitogen-activated protein kinase (MAPK) and other pain-related cytokines such as IL-6, TNF-α and IL-1β.Conclusion: The findings indicate that Mag has antinociceptive effect on neuropathic pain, probably mediated through P2Y12 receptors and p38 MAPK mediated pathways. With its relatively safe profile, Mag may be a potential therapeutic agent for neuropathic pain.Keywords: magnolol, neuropathic pain, P2Y12, CCI, MAPK, cytokines

The P2Y12 receptor is an important member of the purinergic receptor family, known for its critical role in platelet activation and thrombosis. In our previously published study, the acridinone analogue NSC618159 was identified as a potent antagonist of P2Y12. In this work, we investigate the conformational changes in P2Y12 when bound to NSC618159 using molecular dynamics simulations on the receptor’s active and inactive forms (4PXZ and 4NTJ, respectively). It was observed that it took the systems about 7 ns and 12 ns to stabilise when NSC618159 was in complex with the active and inactive forms of P2Y12, respectively. Additionally, the binding pocket of the crystal structure 4PXZ expanded from 172.34 Å3 to an average of 661.55 Å3 when bound to NSC618159, with a maximum pocket volume of 820.49 Å3. This expansion was attributed to the pulled away transmembrane (TM) helices and the adoption of a more open conformation by extracellular loop 2 (EL2). In contrast, 4NTJ’s pocket volume was mostly consistent and had an average of 1203.82 Å3. Moreover, the RMSF profile of the NSC618159-4PXZ complex showed that residues of TM-I and TM-VII had similar fluctuations to the 4NTJ crystal structure, representing the inactive form of P2Y12. Finally, the energy components and binding affinities of NSC618159 towards the active and inactive forms of P2Y12 were predicted using the MM-PBSA approach. According to the results, the binding affinity of NSC618159 towards both active (4PXZ) and inactive (4NTJ) forms of P2Y12 was found to be almost identical, with values of −43.52 and −41.68 kcal/mol, respectively. In conclusion, our findings provide new insights into the conformational changes of P2Y12 upon binding to NSC618159 and may have implications for the development of new P2Y12 antagonists with enhanced potency and specificity.

Debates persist regarding the optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in coronary artery disease (CAD). Recent trials have introduced a novel approach involving P2Y12 inhibitor monotherapy with ticagrelor or clopidogrel, after a short DAPT. However, the effectiveness and safety of this strategy remains to be established. We aimed to perform a meta-analysis comparing monotherapy with P2Y12 inhibitors versus standard DAPT in patients undergoing PCI at 12 months. Multiple databases were searched. Six RCTs with a total of 24877 patients were included. The primary endpoint was all-cause mortality at 12 months of follow-up. The secondary endpoints were cardiovascular mortality, myocardial infarction, probable or definite stent thrombosis, stroke events, and major bleeding. The study is registered with PROSPERO (CRD42024499529). Monotherapy with P2Y12 inhibitor ticagrelor significantly reduced both allcause mortality (HR 0.71, 95 CI [0.55-0.91], P = 0.007) and cardiovascular mortality (HR 0.66, 95% CI [0.49-0.89], P = 0.006) compared to standard DAPT. In contrast, clopidogrel monotherapy did not demonstrate a similar reduction. The decrease in mortality associated with ticagrelor was primarily due to a lower risk of major bleeding (HR 0.56, 95% CI [0.43-0.72], P < 0.001), while the risk of myocardial infarction (MI) remained unchanged (HR 0.90, 95% CI [0.73-1.11], P = 0.32). The risk of stroke was found to be similar across treatments. In comparison to standard DAPT, P2Y12 inhibitor monotherapy with ticagrelor may lead to a reduced mortality. The clinical benefits are driven by a reduction of bleeding risk without ischemic risk trade-off. What Is New? • The current meta-analysis showed that mortality is lower in patients treated with P2Y 12 monotherapy compared to standard dual antiplatelet therapy (DAPT), primarily driven by reduced bleeding risks. • Among different P2Y 12 inhibitors, ticagrelor shows greater effectiveness in reducing mortality compared to clopidogrel when used as monotherapy following a short course of DAPT. • The study demonstrates consistency in the effectiveness of P2Y 12 inhibitor monotherapy, indicated by a 0 % I2 value for mortality differences when comparing ticagrelor and clopidogrel monotherapy to standard DAPT, suggesting no observed heterogeneity across the included trials. Bayesian meta-analysis confirmed the findings for mortality from the frequentist meta-analysis. What Are the Clinical Implications? • This meta-analysis supports a paradigm shift in antithrombotic therapy, emphasizing a balance between ischemic prevention and bleeding risk. P2Y12 inhibitor monotherapy, especially with ticagrelor, appears to optimize this balance. • The findings suggest that a shorter duration of DAPT (up to 3 months), followed by P2Y12 inhibitor monotherapy with ticagrelor, may significantly reduce mortality, offering a safer and effective alternative to prolonged standard DAPT. • The reduced mortality associated with P2Y12 monotherapy, especially due to the lower risk of bleeding, highlights the need for personalized antithrombotic strategies. [ABSTRACT FROM AUTHOR]

People living with HIV (PLWHIV) present an increased risk of adverse cardiovascular events. We aimed to assess whether antiretroviral therapy (ART) pharmacologically enhances platelet reactivity and platelet activation intensity, and explore the potential association with underlying inflammatory status. This was a cross-sectional cohort study carried out among PLWHIV on diverse ART regimens. Platelet reactivity and activation intensity were assessed using the bedside point-of-care VerifyNow assay, in P2Y12 reaction units (PRU), measurements of monocyte-platelet complexes, and P-selectin and GPIIb/IIIa expression increase, following activation with ADP, respectively. Levels of major inflammatory markers and whole blood parameters were also evaluated. In total, 71 PLWHIV, 59 on ART and 22 healthy controls, were included in this study. PRU values were significantly elevated in PLWHIV compared to controls [Mean; 257.85 vs. 196.67, p < 0.0001], but no significant differences were noted between ART-naïve or ART-experienced PLWHIV, or between TAF/TDF and ABC based regimens, similar to systemic inflammatory response. However, within-group analysis showed that PRUs were significantly higher in ABC/PI vs ABC/INSTI or TAF/TDF + PI patients, in line with levels of IL-2. PRU values did not correlate strongly with CD4 counts, viral load, or cytokine values. P-selectin and GPIIb/IIIa expression increased following ADP activation and were significantly more prominent in PLWHIV (p < 0.005). Platelet reactivity and platelet activation intensity were shown to be increased in PLWHIV, but they did not appear to be related to ART initiation, similar to the underlying systemic inflammatory response.

Simple Summary: Acute Coronary Syndrome is a disease of the circulatory system characterized by the partial or complete blockage of coronary arteries. In thrombosis, a major role is played by platelets—the smallest, anucleate, morphotic elements in the bloodstream. Platelets are involved in the process of hemostasis, which ensures the continuity of the blood vessel by forming a clot that prevents blood loss. Unique structures of blood platelets ensure their high reactivity in the vascular microenvironment due to the interaction with many biologically active molecules, which is recognized by the surface receptors. The research carried out in the manuscript is aimed at detecting potential changes at the molecular level in platelet surface receptors that could constitute the potential importance of the occurrence of Acute Coronary Syndrome. The obtained results indicate that the P2Y12 receptor, which is the main target of antiplatelet therapy, is expressed more frequently among patients. In addition, we have shown that at the genetic level, quantitative changes also occur in the case of other receptors that are important in the activation of platelets. The following manuscript suggests the potential mechanisms responsible for the differences between patients and healthy donors due to a better understanding of the molecular causes of Acute Coronary Syndrome pathogenesis. The pathological conditions caused by blood platelet activation constitute a fundamental core in the pathogenesis of Acute Coronary Syndrome (ACS). The hyperactivity of platelets in ACS is well-documented, but there is still little research into the molecular basis of phenotypic changes in platelet functionality. To expand the knowledge of this phenomenon, we analyzed the disturbances in the expression of several key platelet receptors and the aspect of regulating potential abnormalities. Platelet surface receptors are responsible for maintaining the hemostatic balance, platelet interaction with immune cells, and support of the coagulation cascade leading to occlusion of the vessel lumen. Due to their prominent role, platelet receptors constitute a major target in pharmacological treatment. Our work aimed to identify the molecular alteration of platelet surface receptors, which showed augmented mRNA expression of P2Y12, GP1BB, ITGA2B, and ITGB3 and increased protein concentrations of P2Y12 and GP IIb/IIIa in ACS. The upregulation of the P2Y12 level was also confirmed by confocal and cytometric visualization. Furthermore, we evaluated the expression of two microRNAs: miR-223-3p and miR-126-3p, which were suggested to regulate platelet P2Y12 expression. Results of our study present new insight into the molecular background of ACS. [ABSTRACT FROM AUTHOR]