Inhibition Of Platelet Aggregation Research Articles

Perioperative Plasma in Addition to Red Blood Cell Transfusions Is Associated With Increased Venous Thromboembolism Risk Postoperatively.

Perioperative red blood cell (RBC) transfusions increase venous thromboembolic (VTE) events. Although a previous study found that plasma resuscitation after trauma was associated with increased VTE, the risk associated with additional perioperative plasma is unknown. A US claims and EHR database (TriNetX Diamond Network) was queried. We compared surgical patients who received perioperative plasma and RBC to patients who received perioperative RBC but not plasma. Subanalyses included (1) all surgeries (n = 48,580) and (2) cardiovascular surgeries (n = 38,918). Propensity score matching was performed for age at surgery, ethnicity, race, sex, overweight and obesity, type 2 diabetes, disorders of lipoprotein metabolism, essential hypertension, neoplasms, nicotine dependence, coagulopathies, sepsis, chronic kidney disease, liver disease, nonsteroidal anti-inflammatory analgesics, platelet aggregation inhibitors, anticoagulants, hemoglobin level, outpatient service utilization, and inpatient services; surgery type was included for "all surgeries" analyses. Outcomes included 30-day mortality, postoperative VTE, pulmonary embolism (PE), and disseminated intravascular coagulation (DIC). After matching the surgical cohorts, compared to only RBC, plasma + RBC was associated with higher risk of postoperative mortality (4.52% vs 3.32%, risk ratio [RR]: 1.36 [95% confidence interval, 1.24-1.49]), VTE (3.92% vs 2.70%, RR: 1.36 [1.24-1.49]), PE (1.94% vs 1.33%, RR: 1.46 [1.26-1.68]), and DIC (0.96% vs 0.35%, RR: 2.75 [2.15-3.53]). Among perioperative cardiovascular patients, adding plasma to RBC transfusion was associated with similar increased risk. When compared with perioperative RBC transfusion, adding plasma was associated with increased 30-day postoperative mortality, VTE, PE, and DIC risk among surgical and cardiovascular surgical patients. Reducing unnecessary plasma transfusion should be a focus of patient blood management to improve overall value in health care.

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

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

Real-World Data Analysis of Patients Affected by Immune-Mediated Thrombotic Thrombocytopenic Purpura in Italy.

Background: The therapeutic management of immune-mediated thrombotic thrombocytopenic purpura (iTTP) has recently benefited from the introduction of caplacizumab, an agent directed at the inhibition of platelet aggregation. This real-world analysis investigated the epidemiology and the demographic and clinical characteristics of iTTP patients in Italy before and after caplacizumab introduction in 2020. Methods: Hospitalized adults with iTTP were included using the administrative databases of healthcare entities covering 17 million residents. Epidemiological estimates of iTTP considered the 3-year period before and after caplacizumab introduction. After stratification by treatment with or without caplacizumab, iTTP patients were characterized for their baseline features. Results: The annual incidence before and after 2020 was estimated in the range of 4.3-5.8 cases/million and 3.6-4.6 cases/million, respectively. From 2018 to 2022, 393 patients with iTTP were included, and 42 of them were treated with caplacizumab. Caplacizumab-treated patients showed better clinical outcomes, with tendentially shorter hospital stays and lower mortality rates (no treated patients died at either 1 month or 3 months after caplacizumab treatment initiation, compared to 10.5% and 11.1% mortality rates at 1 and 3 months, respectively, of the untreated ones). Conclusions: These findings may suggest that caplacizumab advent provided clinical and survival benefits for patients with iTTP.

Multi-Omics Approaches for Liver Reveal the Thromboprophylaxis Mechanism of Aspirin Eugenol Ester in Rat Thrombosis Model.

Aspirin eugenol ester (AEE) is a novel medicinal compound synthesized by esterifying aspirin with eugenol using the pro-drug principle. Pharmacological and pharmacodynamic experiments showed that AEE had excellent thromboprophylaxis and inhibition of platelet aggregation. This study aimed to investigate the effect of AEE on the liver of thrombosed rats to reveal its mechanism of thromboprophylaxis. Therefore, a multi-omics approach was used to analyze the liver. Transcriptome results showed 132 differentially expressed genes (DEGs) in the AEE group compared to the model group. Proteome results showed that 159 differentially expressed proteins (DEPs) were identified in the AEE group compared to the model group. Six proteins including fibrinogen alpha chain (Fga), fibrinogen gamma chain (Fgg), fibrinogen beta chain (Fgb), orosomucoid 1 (Orm1), hemopexin (Hpx), and kininogen-2 (Kng2) were selected for parallel reaction monitoring (PRM) analysis. The results showed that the expression of all six proteins was upregulated in the model group compared with the control group. In turn, AEE reversed the upregulation trend of these proteins to some degree. Metabolome results showed that 17 metabolites were upregulated and 38 were downregulated in the model group compared to the control group. AEE could reverse the expression of these metabolites to some degree and make them back to normal levels. The metabolites were mainly involved in metabolic pathways, including linoleic acid metabolism, arachidonic acid metabolism, and the tricarboxylic acid (TCA) cycle. Comprehensive analyses showed that AEE could prevent thrombosis by inhibiting platelet activation, decreasing inflammation, and regulating amino acid and energy metabolism. In conclusion, AEE can have a positive effect on thrombosis-related diseases.

Ginkgetin effectively mitigates collagen and AA-induced platelet activation via PLCγ2 but not cyclic nucleotide-dependent pathway in human.

Platelets assume a pivotal role in the cardiovascular diseases (CVDs). Thus, targeting platelet activation is imperative for mitigating CVDs. Ginkgetin (GK), from Ginkgo biloba L, renowned for its anticancer and neuroprotective properties, remains unexplored concerning its impact on platelet activation, particularly in humans. In this investigation, we delved into the intricate mechanisms through which GK influences human platelets. At low concentrations (0.5-1 μM), GK exhibited robust inhibition of collagen and arachidonic acid (AA)-induced platelet aggregation. Intriguingly, thrombin and U46619 remained impervious to GK's influence. GK's modulatory effect extended to ATP release, P-selectin expression, intracellular calcium ([Ca2+ ]i) levels and thromboxane A2 formation. It significantly curtailed the activation of various signaling cascades, encompassing phospholipase Cγ2 (PLCγ2)/protein kinase C (PKC), phosphoinositide 3-kinase/Akt/glycogen synthase kinase-3β and mitogen-activated protein kinases. GK's antiplatelet effect was not reversed by SQ22536 (an adenylate cyclase inhibitor) or ODQ (a guanylate cyclase inhibitor), and GK had no effect on the phosphorylation of vasodilator-stimulated phosphoproteinSer157 or Ser239 . Moreover, neither cyclic AMP nor cyclic GMP levels were significantly increased after GK treatment. In mouse studies, GK notably extended occlusion time in mesenteric vessels, while sparing bleeding time. In conclusion, GK's profound impact on platelet activation, achieved through inhibiting PLCγ2-PKC cascade, culminates in the suppression of downstream signaling and, ultimately, the inhibition of platelet aggregation. These findings underscore the promising therapeutic potential of GK in the CVDs.

Analysis of the prevalence of anticoagulant therapy in patients with cognitive disorders and cerebral amyloid angiopathy (CAA)

To investigate the prevalence of coincident anticoagulation in patients with cognitive disorders and possible or probable cerebral amyloid angiopathy (CAA) as well as the relationship between the presence of oral anticoagulation and CAA-specific lesion load. Patients with subjective cognitive decline (SCD), amnestic and non-amnestic mild cognitive impairment (aMCI/naMCI), Alzheimer's disease (AD), mixed dementia (MD) and vascular dementia (VD) who presented to our outpatient dementia clinic between February 2016 and October 2020 were included in this retrospective analysis. Patients underwent cranial magnetic resonance imaging (MRI). MRI data sets were analyzed regarding the presence of CAA-related MRI biomarkers to determine CAA prevalence. Presence of anticoagulant therapy was determined by chart review. Within the study period, 458 patients (209 male, 249 female, mean age 73.2 ± 9.9years) with SCD (n = 44), naMCI (n = 40), aMCI (n = 182), AD (n = 120), MD (n = 68) and VD (n = 4) were analyzed. Atotal of 109 patients (23.8%) were diagnosed with possible or probable CAA. CAA prevalence was highest in aMCI (39.4%) and MD (28.4%). Of patients with possible or probable CAA, 30.3% were under platelet aggregation inhibition, 12.8% were treated with novel oral anticoagulants and 3.7% received phenprocoumon treatment. Regarding the whole study cohort, patients under oral anticoagulation showed more cerebral microbleeds (p = 0.047). There was no relationship between oral anticoagulation therapy and the frequency of cortical superficial siderosis (p = 0.634). CAA is afrequent phenomenon in older patients with cognitive disorders. Almost half of CAA patients receive anticoagulant therapy. Oral anticoagulation is associated with ahigher number of cortical and subcortical microbleeds.

A Chromosome-Level Genome Assembly of the Non-Hematophagous Leech Whitmania pigra (Whitman 1884): Identification and Expression Analysis of Antithrombotic Genes.

Despite being a non-hematophagous leech, Whitmania pigra is widely used in traditional Chinese medicine for the treatment of antithrombotic diseases. In this study, we provide a high quality genome of W. pigra and based on which, we performed a systematic identification of the potential antithrombotic genes and their corresponding proteins. We identified twenty antithrombotic gene families including thirteen coagulation inhibitors, three platelet aggregation inhibitors, three fibrinolysis enhancers, and one tissue penetration enhancer. Unexpectedly, a total of 79 antithrombotic genes were identified, more than a typical blood-feeding Hirudinaria manillensis, which had only 72 antithrombotic genes. In addition, combining with the RNA-seq data of W. pigra and H. manillensis, we calculated the expression levels of antithrombotic genes of the two species. Five and four gene families had significantly higher and lower expression levels in W. pigra than in H. manillensis, respectively. These results showed that the number and expression level of antithrombotic genes of a non-hematophagous leech are not always less than those of a hematophagous leech. Our study provides the most comprehensive collection of antithrombotic biomacromolecules from a non-hematophagous leech to date and will significantly enhance the investigation and utilization of leech derivatives in thrombosis therapy research and pharmaceutical applications.

Inhibition of mitochondrial calcium transporters alters adp-induced platelet responses.

ADP-stimulated elevation of cytosolic Ca2+ is an important effector mechanism for platelet activation. The rapidly elevating cytosolic Ca2+ is also transported to mitochondrial matrix via Mitochondrial Ca2+ Uniporter (MCU) and extruded via Na+/Ca2+/Li+ Exchanger (NCLX). However, the exact contribution of MCU and NCLX in ADP-mediated platelet responses remains incompletely understood. The present study aimed to elucidate the role of mitochondrial Ca2+ transport in ADP-stimulated platelet responses by inhibition of MCU and NCLX with mitoxantrone (MTX) and CGP37157 (CGP), respectively. As these inhibitory strategies are reported to cause distinct effects on matrix Ca2+ concentration, we hypothesized to observe opposite impact of MTX and CGP on ADP-induced platelet responses. Platelet aggregation profiling was performed by microplate-based spectrophotometery while p-selectin externalization and integrin αIIbβ3 activation were analyzed by fluorescent immunolabeling using flow cytometery. Our results confirmed the expression of both MCU and NCLX mRNAs with relatively low abundance of NCLX in human platelets. In line with our hypothesis, MTX caused a dose-dependent inhibition of ADP-induced platelet aggregation without displaying any cytotoxicity. Likewise, ADP-induced p-selectin externalization and integrin αIIbβ3 activation was also significantly attenuated in MTX-treated platelets. Concordantly, inhibition of NCLX with CGP yielded an accelerated ADP-stimulated platelet aggregation which was associated with an elevation of p-selectin surface expression and αIIbβ3 activation. Together, these findings uncover a vital and hitherto poorly characterized role of mitochondrial Ca2+ transporters in ADP-induced platelet activation.

Synthesis and Biological Evaluation of Novel Thiadiazole Derivatives as Antiplatelet Agents.

A novel series of thiadiazole compounds was synthesized through the reaction of thiosemicarbazone intermediates with 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The antiplatelet activity of the synthesized compounds was evaluated using an aggregation test with adenosine diphosphate (ADP) and arachidonic acid (AA) as platelet aggregation inducers. Among the synthesized analogs, compound 3b exhibited the most potent inhibition of platelet aggregation induced by ADP (half maximal inhibitory concentration [IC50] = 39 ± 11 µM). Molecular docking studies of 3b revealed hydrogen bonds between the nitrogen of the thiadiazole ring and Lys280. The tolyl ring exhibited hydrophobic interactions with Tyr105, similar to the antagonist co-crystallized with P2Y12 (PDB ID: 4NTJ). These compounds have the potential to serve as lead molecules for designing P2Y12 inhibitors.

Anti-fibrinolytic activity, electron delocalization, vibrational spectra, drug - likeness properties and bio-activity studies on Anagrelide

DFT-based quantum mechanical calculations, electron behaviour, biological properties of the Anagrelide with an IUPAC name of (6,7-dichloro-3,5-dihydro-1H-Imidazo[2,1,-b]quinazolin-2-one) is probed using Gaussian 09 W and Gauss View 6 programs, with B3LYP / 6–311++ G (d, p) basis set. The optimized geometrical properties and structure were tabulated and modelled. A systematic approach has been adopted for FTIR and Raman spectroscopic studies and its vibrational PED% assignments, with the help of VEDA software, were employed. NLO properties and its calculations in gas phase, and four sets of green solvents were calculated. Simulated UV spectroscopy analysis was explored using the TD-DFT with the IEFPCM model, and spectrum was made using the help of Gauss-sum. Since there is a correlation between the energy of the FMOs and their optical properties, those orbitals were mapped, and ΔEHomo-Lumo (ΔE) values were evaluated. NBO analysis has been employed to examine the stability, resulting from its intra-molecular and intermolecular hyper conjugative interactions owing to charge delocalization. Mulliken's charges distribution of the title molecule was computed to look at theirelectrophilic and nucleophilic activities. Analyses of the MESP were carried out for various solvents. Anagrelide was theoretically subjected to an explicit topological surface analysis using the wavefunction analyzer and multiwfn software to look at the compound's reactivity and wave functional properties LOL, and ELF. In order to study the biological activity as an anticoagulant,a platelet aggregation inhibitor, and a vasodilator, Anagrelidewas utilized as a ligand with several target proteins in molecular docking and Drug-likeliness. The outcomes of molecular docking experiments proved the ligand's potency as an antifibrinolytic medication.

A Review on Radix Scutellariae: A Traditional Chinese Medicine with Great Medicinal Significant

Abstract Radix Scutellariae (RS) refers to the root of Scutellaria baicalensis Georgi (SBG) plant. This plant belongs to family Lamiaceae. There are many common names of RS such as huang chin, huang lien, huang qin, huangqin, and wogon. SBG plant is spreading throughout many Asian countries such as China, Japan, North and South Korea, Mongolia and Russia. The aim of this review is to focus on the ingredients, medicinal uses, pharmacological activity, toxicology, adverse effects, precautions, and dosage of RS. RS contains baicalein, baicalin, wogonin, wogonoside, and oroxylin A ingredients. RS is used in the treatment of fever, nausea and vomiting, acute dysentery, jaundice, coughs, carbuncles and sores, and threatened abortion. RS is applied in the treatment of allergies, arteriosclerosis, diarrhea, dermatitis, and hypertension. Pharmacology activity of RS includes experimental pharmacology and clinical pharmacology. Experimental pharmacology contains hepatoprotective, anti-inflammatory, antioxidant, antimicrobial, anti-tumor, antiviral, central nervous system, enzyme inhibition, immunological, platelet aggregation inhibition, and smooth muscle activities. Injection of water extract of RS (12–15 g/kg, intragastrically) to dogs without any toxic effects and the oral intake of 4–5 g/kg of this extract to dogs three times/day for 8 weeks did not induce any toxic effects. There are no carcinogenesis, mutagenesis, and impairment of fertility, pregnancy, teratogenic effects or any other effects of RS. RS possesses many pharmacological activities and it is used to treat many diseases and without any toxic effect to any organs.

"In Vitro Evaluation of the Antiplatelet Activity of Paravat Shakrita"

Platelet aggregation, a crucial process in thrombotic disorders, underscores the necessity for effective preventive and therapeutic measures. This study compares the antiplatelet effects of Aspirin, a well-established drug, with Paravat Shakrita, a lesser-known formulation from Ayurvedic texts. It underwent GCMS and microbiological analysis to determine its chemical composition and microbial load. Using an in vitro model with rat blood samples, we conducted a Platelet Aggregation Inhibition Assay. As expected, Aspirin inhibited platelet aggregation in a concentration-dependent manner, consistent with its known mechanism. Despite limited documentation, Paravat Shakrita exhibited potent antiplatelet properties, also showing dose-dependent effects. Interestingly, Paravat Shakrita demonstrated comparable or even superior effects at higher concentrations compared to Aspirin. The IC50 values revealed similar inhibitory potency between Paravat Shakrita and Aspirin. This comparison unveiled distinct mechanisms of action, providing various therapeutic options against platelet-mediated thrombosis. While promising, further investigation is crucial to understand Paravat Shakrita's mechanism, ensure its safety, and determine its clinical significance.

Construction and study of blood purification membrane modified with PDE inhibitor: Investigation of antiplatelet activity and hemocompatibility

The recent “cell-based theory” of coagulation suggests that platelets serve as the site of coagulation factor reactions, making platelets an effective target for inhibiting membrane thrombosis. Unfortunately, there is limited research on how blood purification membranes affect platelet intracellular signaling. In this study, we modified polyethersulfone (PES) membranes with the platelet phosphodiesterase (PDE) inhibitor dipyridamole (DIP) and investigated the effects of the DIP/PES (DP) membranes on platelet adhesion, activation, aggregation, and secretion, as well as the role of the PDE-cyclic adenosine monophosphate (cAMP) intracellular signaling pathway. Additionally, we evaluated the hemocompatibility and preliminary in vivo safety of DP membranes. Our results demonstrate that the modified DP membranes effectively inhibited platelet adhesion, membrane CD62P expression, and plasma soluble P-selectin activation levels. Furthermore, we confirmed that DP membranes achieved platelet aggregation inhibition and reduced platelet factor 4 and β-thromoglobulin secretion levels by inhibiting platelet intracellular PDE-cAMP signaling. Moreover, the modified DP membranes exhibited good anticoagulant and red blood cell membrane stability and complement resistance and demonstrated preliminary biocompatibility in mouse experiments. Collectively, these findings highlight the potential application of DP dialysis membranes in blood purification for critically ill patients.

Hydrogen sulfide in the cardiovascular system: A small molecule with promising therapeutic potential

This review summarizes current knowledge of the hydrogen sulfide role in cardiovascular system, the proposed mechanisms of its action and the prospects for its applicability in the treatment of cardiovascular diseases. Hydrogen sulfide was recently recognized as gasotransmitter –simple signaling molecule which freely penetrates the cell membrane and regulates a number of biological functions. In humans endogenous H2S is generated via enzymatic and non-enzymatic pathways and its content varies in different tissues and is strictly regulated. In cardiovascular system H2S is produced by myocardial, vascular and blood cells and regulates a number of vital functions. Numerous experimental data prove that endogenously generated as well as exogenously administered H2S exerts a wide range of actions in cardiovascular system, including vasodilator/vasoconstrictor effects, regulation of blood pressure, pro-apoptotic and anti-proliferative effects in the vascular smooth muscle cells, influence on angiogenesis and erythropoiesis, myocardial cytoprotection in ischemia-reperfusion injury, oxygen sensing, inhibition of platelet aggregation and blood coagulation, modification of erythrocyte microrheological properties (aggregability and deformability). Understanding of molecular mechanisms of H2S action and molecular crosstalk between H2S, NO, and CO is essential for the development of its diagnostic and therapeutic potential.

Evaluation of the antiplatelet effect of generic ticagrelor 90 mg (ticaspan ® ) alone and in combination with aspirin 75 mg as compared to ticagrelor (innovator): An in vitro study.

To evaluate an in vitro antiplatelet effect of generic ticagrelor 90 mg (ticaspan) alone and in combination with aspirin 75 mg as compared to the innovator formulation of ticagrelor alone and in combination with aspirin among healthy Indian volunteers. 18 volunteers were enrolled and platelet viability was tested using lactate dehydrogenase (LDH) assay in six of 18 volunteers. In 12 volunteers, maximum platelet aggregation (MPA) and percentage inhibition of platelet aggregation (PI) were assessed using a platelet aggregometer in six study groups. There was no significant increase in LDH levels when platelets were incubated with an innovator or generic drug alone and in combination with aspirin as compared to the dimethyl sulfoxide [DMSO] group. All five study groups showed a significant reduction in the MPA values compared to the DMSO group ( P < 0.01). The extent of decrease in MPA observed with the generic drug was not significantly different from the innovator drug ( P = 0.325). Similarly, the MPA observed with the two combination groups did not differ from each other ( P = 1.000), but it was significantly different from the MPA observed with aspirin ( P = 0.039, each). The PI of platelet aggregation was significantly more in four study groups [generic drug alone; innovator alone; generic drug + aspirin; and innovator drug + aspirin] ( P < 0.01) as compared to the aspirin group. The generic ticagrelor and its combination with aspirin demonstrated an antiplatelet effect equivalent to the innovator drug and its combination with aspirin.

Statins Effects on Blood Clotting: A Review.

Statins are powerful lipid-lowering drugs that inhibit cholesterol biosynthesis via downregulation of hydroxymethylglutaryl coenzyme-A reductase, which are largely used in patients with or at risk of cardiovascular disease. Available data on thromboembolic disease include primary and secondary prevention as well as bleeding and mortality rates in statin users during anticoagulation for VTE. Experimental studies indicate that statins alter blood clotting at various levels. Statins produce anticoagulant effects via downregulation of tissue factor expression and enhanced endothelial thrombomodulin expression resulting in reduced thrombin generation. Statins impair fibrinogen cleavage and reduce thrombin generation. A reduction of factor V and factor XIII activation has been observed in patients treated with statins. It is postulated that the mechanisms involved are downregulation of factor V and activated factor V, modulation of the protein C pathway and alteration of the tissue factor pathway inhibitor. Clinical and experimental studies have shown that statins exert antiplatelet effects through early and delayed inhibition of platelet activation, adhesion and aggregation. It has been postulated that statin-induced anticoagulant effects can explain, at least partially, a reduction in primary and secondary VTE and death. Evidence supporting the use of statins for prevention of arterial thrombosis-related cardiovascular events is robust, but their role in VTE remains to be further elucidated. In this review, we present biological evidence and experimental data supporting the ability of statins to directly interfere with the clotting system.

Are breast cancer patients with suboptimal adherence to cardiovascular treatment more likely to discontinue adjuvant endocrine therapy? Competing risk survival analysis in a nationwide cohort of postmenopausal women

BackgroundHigh rates of discontinuation undermine the effectiveness of adjuvant endocrine therapy (AET) among hormone-receptive breast cancer patients. Patient prognosis also relies on the successful management of cardiovascular risk, which affects a high proportion of postmenopausal women. As with AET, adherence with cardiovascular drugs is suboptimal. We examined whether patient adherence with cardiovascular drugs was associated with the rate of AET discontinuation in a French nationwide claims database linked with hospitalisation data.MethodsWe identified postmenopausal women starting AET between 01/01/2016 and 31/12/2020 and taking at least two drugs for the primary prevention of cardiovascular disease (antihypertensive drugs, lipid-lowering drugs and platelet aggregation inhibitors) before AET initiation. Adherence was assessed for each drug class by computing the proportion of days covered. Women were categorised as fully adherent, partially adherent or fully non-adherent with their cardiovascular drug regimen based on whether they adhered with all, part or none of their drugs. AET discontinuation was defined as a 90-day gap in AET availability. Time to AET discontinuation according to levels of cardiovascular drug adherence was estimated using cumulative incidence curves, accounting for the competing risks of death and cancer recurrence. Multivariate cause-specific Cox regressions and Fine-and-Gray regressions were used to assess the relative hazards of AET discontinuation.ResultsIn total, 32,075 women fit the inclusion criteria. Women who were fully adherent with their cardiovascular drugs had the lowest cumulative incidence of AET discontinuation at any point over the 5-year follow-up period. At 5 years, 40.2% of fully non-adherent women had discontinued AET compared with 33.5% of partially adherent women and 28.8% of fully adherent women. Both partial adherence and full non-adherence with cardiovascular drugs were predictors of AET discontinuation in the two models (cause-specific hazard ratios 1.16 [95% CI 1.10–1.22] and 1.49 [95% CI 1.39–1.58]; subdistribution hazard ratios 1.15 [95% CI 1.10–1.21] and 1.47 [95% CI 1.38–1.57]).ConclusionClinicians should be aware that patients who do not adhere with their entire cardiovascular drug regimen are also more likely to discontinue AET. This stresses the importance of integrated care, as suboptimal adherence with both treatment components poses a threat to achieving ideal patient outcomes.

Revisiting the Asian Buffalo Leech (Hirudinaria manillensis) Genome: Focus on Antithrombotic Genes and Their Corresponding Proteins.

Leeches are well-known annelids due to their obligate blood-feeding habits. Some leech species secrete various biologically active substances which have important medical and pharmaceutical value in antithrombotic treatments. In this study, we provided a high-quality genome of the Asian buffalo leech (Hirudinaria manillensis), based on which we performed a systematic identification of potential antithrombotic genes and their corresponding proteins. Combining automatic and manual prediction, we identified 21 antithrombotic gene families including fourteen coagulation inhibitors, three platelet aggregation inhibitors, three fibrinolysis enhancers, and one tissue penetration enhancer. A total of 72 antithrombotic genes, including two pseudogenes, were identified, including most of their corresponding proteins forming three or more disulfide bonds. Three protein families (LDTI, antistasin, and granulin) had internal tandem repeats containing 6, 10, and 12 conserved cysteines, respectively. We also measured the anticoagulant activities of the five identified hirudins (hirudin_Hman1 ~ hirudin_Hman5). The results showed that three (hirudin_Hman1, hirudin_Hman2, and hirudin_Hman5), but not the remaining two, exhibited anticoagulant activities. Our study provides the most comprehensive collection of antithrombotic biomacromolecules from a leech to date. These results will greatly facilitate the research and application of leech derivatives for medical and pharmaceutical purposes in the treatment of thrombotic diseases.

In vitro comparison of platelet aggregation between zalunfiban and selatogrel in healthy donors

Abstract Background Two subcutaneously injected antiplatelet drugs, zalunfiban and selatogrel, are under development for prehospital administration for STEMI and (N)STEMI, respectively. Zalunfiban is a glycoprotein IIb/IIIa inhibitor that produces high-grade inhibition of platelet aggregation induced by ADP or a thrombin receptor activating peptide (TRAP) within 15 minutes. Selatogrel is a P2Y12 inhibitor that produces high-grade inhibition of platelet aggregation initiated by ADP within 15 minutes. We have studied the relative potencies of the drugs at levels achievable in vivo in inhibiting platelet aggregation. Since trisodium citrate (TSC) has been reported to enhance the antiplatelet effect of zalunfiban and inhibit the antiplatelet effect off selatogrel, aggregation studies were performed with both blood anticoagulated with TSC and the non-chelating anticoagulant PPACK. Whereas both ADP and thrombin are present at the site of vascular injury within seconds, we tested the effects of both ADP and TRAP. Purpose To compare directly the effects of zalunfiban and selatogrel on ADP- and TRAP-induced platelet aggregation. Methods Light transmission platelet aggregometry was performed within 4 hours of blood collection (BioData PAP-8E). Whole blood from healthy donors not taking aspirin (N=10) was anticoagulated with 3.2% TSC and 100 μM PPACK. Platelet-rich plasma (PRP) was prepared and adjusted to a platelet count of 250,000/µl. Three clinically relevant incremental concentrations of zalunfiban and selatogrel were added to PRP and platelet aggregation was initiated with 20 μM ADP or 20 μM TRAP. Tracings were recorded for at least 10 minutes after agonist addition. Platelet aggregation was quantified based on the instrument’s measurement of the primary slope (PrSl) of aggregation, which is a measure of the change in light transmission per unit time sustained over at least a 15 second period. Results In TSC-anticoagulated PRP, zalunfiban was more effective in inhibiting the PrSl of both ADP- and TRAP-induced platelet aggregation at all drug concentrations [Figure 1, panel A and B]. In PPACK-anticoagulated PRP, selatogrel showed greater inhibition of ADP-induced platelet aggregation at the lowest concentration tested, similar inhibition at the intermediate concentration, and slightly less inhibition at the highest doses. In sharp contrast, with TRAP-induced aggregation, zalunfiban demonstrated dose-related inhibition, reaching greater than 80% inhibition at the highest dose, whereas selatogrel produced less than 20% inhibition at all three doses. Conclusion Selatogrel is a potent inhibitor of ADP-induced platelet aggregation, but has low impact on TRAP-induced platelet aggregation, whereas zalunfiban is a potent inhibitor of both ADP and TRAP-induced platelet aggregation. The difference between the drugs needs to be considered in light of the known generation of thrombin at the site of vascular injury within seconds.Comparison of Platelet Inhibition

Abstract 13963: Redefining the Assessment of “Therapeutic” Platelet Response to Acetylsalicylic Acid

Background: Despite extensive investigations, the optimal assessment of the “therapeutic response” to acetylsalicylic acid (ASA) remains unclear. Limited information is available on the relation between serum thromboxane (Tx)B 2 ; arachidonic acid (AA)-induced platelet aggregation (PA) by light transmittance aggregometry (LTA); aspirin reaction units (ARU) by VerifyNow aspirin test (VN), and pharmacokinetics (PK). Methods: Serial PD and PK analyses were performed immediately after a single 162 or 650 mg dose of chewed and swallowed ASA in ten healthy volunteers. ASA response was defined as &gt;95% inhibition of serum TxB 2, &lt;550 ARU by VN test and ≤20% AA-induced PA. Correlation analyses between PK and PD measurements and receiver operating characteristic (ROC) curve analyses were performed. Results: ASA Response measured by VN, and AA-induced PA was achieved within 30 minutes of ASA administration. A good correlation was observed between VN ARU and 1 mM AA-induced maximum PA (r=0.80, p&lt;0.001), serum TxB 2 (r=0.76, p&lt;0.001), and inhibition of serum TxB 2 (r=0.87, p&lt;0.001). The relation between platelet aggregation and TxB 2 inhibition appears to be dichotomous, with only modest inhibition of TxB 2 (~50% inhibition) associated with marked inhibition of platelet aggregation. ROC curve analyses indicated that ≤558 ARU and ≤7% AA-induced PA were associated with &gt;95% inhibition of TxB 2 . A plasma ASA 686 ng/mL cut-off was associated with &gt;95% inhibition of serum TxB 2 , ≤7% 1 mM AA-induced PA by LTA, and ≤585 ARU. Conclusion: Our study demonstrated an important relationship between PD and PK parameters measured immediately following oral ASA and cutoff values for VN assay and LTA that is associated with &gt;95% inhibition of serum TxB 2 . We demonstrated that ~50% inhibition of TxB 2 is required to reach high levels of platelet function inhibition.