ADP-induced Platelet Aggregation Research Articles

Clinical prediction factors of nonchronic total occlusion lesion progression in patients with unstable angina receiving percutaneous coronary intervention for chronic total occlusion lesions

BackgroundIn this study, we investigated clinical prediction factors of nonchronic total occlusion lesion (NCTOL) progression in patients who underwent percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) lesions. MethodsIn total, 450 patients with unstable angina (mean age = 57.1 ± 9.2 years) who underwent PCI for CTO lesions between January 2016 and December 2018 at Beijing Anzhen Hospital were enrolled in this study. A clinical and angiographic follow-up examination was performed 12 months postoperatively. The patients were divided into NCTOL progression (145 cases) and control (305 cases) groups based on the outcome of the 12-month angiographic follow-up. The clinical and angiographic features of the participants were analyzed. ResultsThe adenosine diphosphate-induced platelet aggregation (ADP-IPA) rate and levels of lipoprotein (a) (Lp(a)) in the NCTOL progression group were significantly higher than those in the control group (51.89 ± 14.81 vs. 39.63 ± 17.12, P < 0.01; 0.22 ± 0.26 vs. 0.14 ± 0.18, P < 0.05, respectively). Logistic regression showed that the ADP-IPA rate (odds ratio = 1.047, 95 % confidence interval: 1.014–1.082, P = 0.005) and Lp(a) (odds ratio = 11.972, 95 % confidence interval: 1.230–116.570, P = 0.033) were independent predictors of NCTOL progression. Partial correlation analysis demonstrated that the ADP-IPA rate was positively correlated with NCTOL progression (r = 0. 351, P < 0.001). Receiver operating characteristic curve showed that the boundary point of the ADP-IPA rate to predict NCTOL progression was 30 % (sensitivity, 86.2 %; specificity, 68.9 %). ConclusionsNCTOL progression is an important cause of recurrent PCI in patients with coronary artery disease after PCI for CTO lesions. The ADP-IPA rate is a useful predictor for NCTOL progression in patients with unstable angina who undergo PCI for CTO lesions.

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.

Role of &lt;i&gt;ITGB3&lt;/i&gt;, &lt;i&gt;GP1B1&lt;/i&gt;, and &lt;i&gt;ITGA2&lt;/i&gt; gene polymorphisms in platelet dysfunction in patients with COVID-19-associated lung damage

The aim of the work. To investigate platelet aggregation, polymorphism in the genes that ensure its implementation, and the association between these indicators in patients with COVID-19-associated lung damage, depending on the severity of the clinical course. Methodology. The study involved 75  patients with COVID-19, which, depending on  the severity of lung involvement, were divided into two groups: patients with  damage of up to 50  % of the lung parenchyma (n  =  48) and with damage of more than 50 % (n = 27) respectively. The control group consisted of healthy people (n = 24), comparable in sex and age. In all individuals, the number of platelets, platelet aggregation induced by ADP, collagen and ristomycin were studied; polymorphisms rs6065 in the GP1BA gene, rs1126643 in the ITGA2 gene, and rs5918 in the ITGB3 gene were determined by polymerase chain reaction. The analysis of the obtained data was executed using the IBM SPSS Statistics v. 23 (IMB Corp., USA). Results and discussion. In patients with moderate and severe COVID-19-associated lung damage, platelet aggregation induced by ADP, collagen, and ristomycin accelerated; in severe cases, the number of  platelets decreased. The frequency of variants of the rs6065 polymorphism did not change, the frequency of occurrence of the T/C genotype of the rs5918 polymorphism increased; with moderate severity, the frequency of occurrence of the C/T and T/T genotypes of the rs1126643 polymorphism increased; with severe lung damage, the frequency of occurrence of the mutant C/C genotype polymorphism rs5918 increased. In moderate lung damage, the presence of the  mutant T/T polymorphism rs1126643 accelerated collagen-induced platelet aggregation; in severe cases, the presence of mutant C/C and heterozygous variant C/T polymorphism rs5918 accelerated ADP-induced platelet aggregation. There was no effect of the rs6065 polymorphism on platelet aggregation. The data obtained indicate the possible role of genetic predisposition in the activation of platelet aggregation in patients with COVID-19-associated lung damage.

Phytochemical characterization and phospholipase A2 inhibitory effect of Vitex negundo L. root extracts

Ethnopharmacological relevanceSnake bites are a critical health issue in many parts of the world particularly in Asian countries lacking efficient health facilities in rural areas. Cobra is the most common snake type in Asia and is responsible for a large number of mortalities particularly in rural areas. Plants are usually considered the most effective and easy-to-approach treatment for snake bites in rural areas of various countries. Vitex negundo L. is an important medicinal plant traditionally used to treat snake bite envenomation in many countries of Asia. Aim of the studyFrom literature survey of plants traditionally used in the treatment of snake bites in Asian countries including India, Pakistan and Sri Lanka, roots of V. negundo were selected for the present study. Anti-snake venom potential of its roots was assessed through various in vitro assays targeting the phospholipase A2 enzyme. Materials and methodsV. negundo roots were sequentially extracted in different organic solvents to get fractions and in methanol to get total extract. The extracts were evaluated for phospholipase A2 (PLA2) inhibitory potential through inhibition of venom-induced hemolysis, ADP-induced platelet aggregation, PLA2-induced fatty acid hydrolysis and anticoagulant effect of cobra venom. Antioxidant power was determined using DPPH and superoxide radical scavenging assays. GC-MS and HPLC analysis was performed for the total methanol extract. ResultsStrong PLA2 inhibitory effect was observed for all the extracts. The ethyl acetate, acetone and methanol fractions significantly inhibited toxic effects of cobra venom under in vitro conditions. Radical scavenging potential of these fractions was also significantly high as compared to non-polar fractions in both DPPH and superoxide scavenging assays. Phytochemical analysis indicated high phenolic and flavonoid contents in these fractions. GC-MS and HPLC analysis of total methanol extract confirmed the presence of bis(2-ethylhexyl) phthalate, phenol, o-Guaiacol, palmitic acid-methyl ester, methyl stearate, quercetin and kaempferol in the plant. ConclusionThe study concluded that the roots of V. negundo, particularly their polar extracts, have strong PLA2 inhibitory effect against cobra venom confirming their traditional use to manage snake bites. The roots of this plant can be further studied for isolation of plant-based antisera.

GDF-15 Inhibits ADP-Induced Human Platelet Aggregation through the GFRAL/RET Signaling Complex.

Growth differentiation factor-15 (GDF-15) is proposed to be strongly associated with several cardiovascular diseases, such as heart failure and atherosclerosis. Moreover, some recent studies have reported an association between GDF-15 and platelet activation. In this study, we isolated peripheral blood platelets from healthy volunteers and evaluated the effect of GDF-15 on adenosine diphosphate (ADP)-induced platelet activation using the platelet aggregation assay. Subsequently, we detected the expression of GDF-15-related receptors on platelets, including the epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), human epidermal growth factor receptor 3 (HER3), transforming growth factor-beta receptor I (TGF-βRI), transforming growth factor-beta receptor II (TGF-βRII), glial-cell-line-derived neurotrophic factor family receptor α-like (GFRAL), and those rearranged during transfection (RET). Then, we screened for GDF-15 receptors using the GDF-15-related receptor microarray comprising these recombinant proteins. We also performed the immunoprecipitation assay to investigate the interaction between GDF-15 and the receptors on platelets. For the further exploration of signaling pathways, we investigated the effects of GDF-15 on the extracellular signal-regulated kinase (ERK), protein kinase B (AKT), and Janus kinase 2 (JAK2) pathways. We also investigated the effects of GDF-15 on the ERK and AKT pathways and platelet aggregation in the presence or absence of RET agonists or inhibition. Our study revealed that GDF-15 can dose-independently inhibit ADP-induced human platelet aggregation and that the binding partner of GDF-15 on platelets is GFRAL. We also found that GDF-15 inhibits ADP-induced AKT and ERK activation in platelets. Meanwhile, our results revealed that the inhibitory effects of GDF-15 can be mediated by the GFRAL/RET complex. These findings reveal the novel inhibitory mechanism of ADP-induced platelet activation by GDF-15.

Low ambient temperature exposure increases the risk of ischemic stroke by promoting platelet activation

BackgroundAccumulating epidemiological evidence suggests the association between low ambient temperature exposure and the risk of ischemic stroke, but the underlying mechanisms remain unclear. ObjectiveGiven the crucial role of platelet activation and thrombosis in ischemic stroke, this study aims to investigate the effect of ambient temperature on platelet activation through multi-center clinical data in Tianjin as well as animal experiments. MethodsFrom 2018 to 2020, nearly 3000 ischemic stroke patients from three stroke centers in Tianjin were included in the analysis, among them the ADP induced platelet aggregation rate was available. Meteorological data from the same period had also been collected. After controlling for confounding factors, the generalized additive mixed model (GAMM) was used to evaluate the correlation between environmental temperature and platelet aggregation rate. In further animal experiments, platelet function assessments were conducted on mice from the cold exposure group and the normal temperature group, including platelet aggregation, spreading, and clot retraction. Additionally, tail bleeding and mesentery thrombosis were also tested to monitor hemostasis and thrombosis in vivo. ResultA nonlinear “S” shaped relationship between outdoor temperature and platelet aggregation was found. Each 1 °C decrease of mean temperature was associated with an increase of 7.77 % (95 % CI: 2.06 % - 13.48 %) in platelet aggregation. The ambient temperature is not related to other platelet parameters. Subgroup analysis found that males, people aged ≥65 years, and hypertensive individuals are more susceptible to temperature changes. Furthermore, animal experiments demonstrated that the increased CIRBP levels and subsequent activation of p-AKT/p-ERK may be one of the reasons for cold exposure induced platelets activation. ConclusionBoth clinical data and basic research support that low ambient temperature exposure has the potential to increase platelet activation. These results provide a basis for understanding the potential mechanism of temperature variations on the pathogenesis of cerebrovascular diseases.

Soluble urokinase plasminogen activator receptor, platelet aggregation, and carotid plaque thickness in diabetes: A cross-sectional analysis

BackgroundSoluble urokinase plasminogen activator receptor (suPAR) is an inflammatory biomarker strongly linked with cardiovascular disease in diabetes. By investigating its association with platelet aggregation levels and carotid plaque thickness, we can potentially improve the characterization of cardiovascular pathophysiology in type 1 (T1D) and type 2 diabetes (T2D). MethodsSuPAR was measured post-hoc in plasma collected in two cross-sectional studies including 1) individuals with T1D and 2) individuals with T2D without known cardiovascular disease. Platelet aggregation was analyzed employing impedance aggregometry using the agonists arachidonic acid (ASPI), adenosine diphosphate (ADP), and thrombin receptor activating peptide-6 (TRAP). Carotid plaque thickness was assessed bilaterally, and the thickest plaque (cPTmax) was analyzed. Correlations and associations of suPAR with platelet aggregation and cPTmax were assessed with Pearson's R and linear regressions adjusted for sex, age, C-reactive protein, estimated glomerular filtration rate, and platelet levels (only for aggregation analysis). ASPI analyses were only performed in participant not receiving aspirin treatment. Standardized estimates with 95 % confidence intervals are presented. ResultsTwo-hundred eighty-three with T1D (mean age 55 years, 44 % women) and 493 individuals with T2D (mean age 65 years, 33 % women) were included. SuPAR levels were positively correlated to platelet aggregation in both T1D (ADP: R = 0.18, p = 0.003; ASPI R = 0.13, p = 0.026) and T2D (ADP R = 0.14, p = 0.002; ASPI R = 0.14, p = 0.017). In adjusted linear regressions higher SuPAR levels were associated with higher ADP induced platelet aggregation in both T1D (26 (8, 44) AU/min, p = 0.004) and T2D (22 (3, 42) AU/min, p = 0.025), while associations to the other agonists were not conclusive. Higher suPAR levels were associated with thicker cPTmax in T1D (0.19 (0.07, 0.32) mm, p = 0.003), but not in T2D (p = 0.94). ConclusionHigher levels of suPAR, an inflammatory generalized disease biomarker, were associated with increased platelet aggregation and thicker cPTmax, in type 1 diabetes. Similar associations with platelet aggregation were found in type 2 diabetes, but not for carotid plaque thickness. These results suggest distinct cardiovascular pathomechanisms in T1D and T2D, although prospective studies are needed to confirm these findings.

The Variable Heavy Chain Antibody Syn-VWFA1 Inhibits the Interaction of Platelets to Von Willebrand Factor in Solution but Not to Immobilized Von Willebrand Factor Thereby Inhibiting 3-Dimensional but Not 2-Dimensional Thrombus Formation

Neutralizing the interaction between GP1bα and von Willebrand Factor (VWF) is an attractive strategy for treatment and prevention of platelet-VWF agglutinate formation in von Willebrand disease type 2B and thrombotic thrombocytopenic purpura. The aim of this study was to characterize a llama-derived variable heavy chain antibody (VHH) targeting the A1 domain of active VWF (Syn-VWFA1), in terms of its interference with platelet VWF interaction. Syn-VWFA1 (1.5 µM) abolished platelet binding to ristocetin-activated VWF (native and Haemate® P VWF) and R1306W VWF (VWF type 2B) in a flow-cytometric platelet function assay (Figure 1). Moreover, Syn-VWFA1 dose-dependently inhibited ristocetin-activated VWF and R1306W VWF platelet agglutination, but not collagen- and ADP-induced platelet aggregation. Under flow conditions, Syn-VWFA1 (1.8 µM) did not affect adhesion of platelets to collagen at high shear. In the shear- and collagen-dependent PFA-200, Syn-VWFA1 prolonged the closure time, but only at high concentrations (&amp;gt;3 µM), while GPIba binding to immobilized VWF remained unaffected by Syn-VWFA1. Syn-VWFA1 increased the cleavage of VWF multimers by ADAMTS13. Furthermore, by applying deuterium exchange, we found a small region in the β1 to α1 loop (1288-1293) in the A1 domain of VWF, which is likely to constitute the nanobody binding site (Figure 2) and binding of Syn-VWFA1 to the A1 domain results in a conformational change exposing regions in the α2 and α3 helices. In conclusion, Syn-VWFA1 dose-dependently blocks platelet-binding to activated VWF in solution, but not to (collagen-) immobilized active VWF. This implies that immobilization of VWF to collagen affects VWF conformation in such a way (1) that access of Syn-VWFA1 to its epitope in the A1 domain is hindered or (2) that conformational changes following Syn-VWFA1 binding are blocked, while allowing platelet binding. This implies that Syn-VWFA1 has potential treatment opportunities for patients with increased circulating active VWF, to prevent 3-dimensional thrombus formation (pathological platelet-VWF aggregate formation) but not 2-dimensional thrombus formation (leaving physiological hemostasis at sites of vascular injury intact).

Effect of evolocumab on platelet function in patients with acute coronary syndromes. An analysis of the randomized, double-blind, placebo-controlled EVOPACS Trial

Abstract Background Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors substantially lower levels of low-density lipoprotein cholesterol (LDL-C) and favourably impact clinical outcomes in patients with acute coronary syndromes (ACS). Although PCSK9 inhibitors have been suggested in ex vivo studies to suppress platelet activation, the impact of evolocumab on platelet function in ACS patients receiving potent antiplatelet therapy remains largely unknown. Methods The EVOPACS trial was a randomized, double-blind, placebo-controlled trial assessing the use of evolocumab initiated in the acute phase of ACS. Patients presenting with ST-elevation myocardial infarction (STEMI) or Non-ST-elevation ACS (NSTE-ACS) were randomly allocated in a 1:1 ratio to either evolocumab 420mg SC or matching placebo at baseline (during hospitalization for index ACS event) and after 4 weeks. All patients received atorvastatin 40mg daily. Dual antiplatelet therapy consisting of aspirin and a potent P2Y12 inhibitor was initiated according to STEMI / NSTE-ACS guidelines, unless a less potent treatment was indicated (e.g. due to concomitant use of oral anticoagulation). Platelet function was measured at baseline (during index hospitalization) and after 8 weeks, using the Multiplate analyser. The main outcome for this analysis was the change from baseline to 8 weeks in adenosine diphosphate (ADP)-induced platelet aggregation. Results Serial platelet function measurements were available in 260 of all 308 enrolled patients, 124 in the evolocumab and 136 in the placebo group. Mean age was 60.2±11.0 years and 83% were men. Baseline clinical characteristics were well balanced between the two treatment groups. At discharge, the proportion of patients treated with ticagrelor, prasugrel, and clopidogrel was 73%, 11%, and 9% respectively, without differences between groups. Evolocumab significantly reduced LDL-C compared to placebo at 8 weeks (difference in mean percentage change -40.75%, 95% CI -45.39 to -36.11; p&amp;lt;0.001). Change in ADP-induced platelet aggregation between baseline and 8-week follow-up was -5.6±23.5 U (from 24.1±19.8 to 29.7±25.6 U) in the evolocumab group vs. -1.7±198.7 U (from 23.0±14.7 U to 24.7±19.1 U) in the placebo group (p=0.13). Similar results were found in a subgroup of 189 patients (86 in the evolocumab and 103 in the placebo group) treated with ticagrelor at discharge, showing a change in ADP-induced platelet aggregation of -2.7±19.5 U with evolocumab vs. -2.4±19.9 U with placebo (p=0.80). Conclusions In this randomized trial of ACS patients largely treated with a potent P2Y12 inhibitor, evolocumab initiated during index hospitalization on top of high-intensity statin therapy had no measurable effect on ADP-induced platelet aggregation. These findings suggest that the early therapeutic benefit of PCSK9 inhibitors in ACS patients is likely related to plaque regression/stabilization rather than changes in platelet activity.

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

Designing energy transfer-based color-tunable, information-encrypting, luminous hydro-gels, and latent fingerprint detection systems using BaLa2ZnO5:Tb3+, Bi3+ nanophosphors

Synthesizing cost-effective blue-green emitting BaLa2ZnO5:Tb3+, Bi3+ nanophosphors (BLZO:Tb3+, Bi3+ NPs) through an eco-friendly urea-aided combustion method. Thorough examination of phase purity, structure, surface characteristics, and luminescent properties of the resulting products reveals a robust blue-green emission linked to the 5D4 → 7F5 transition of Tb3+ under 365 nm UV excitation, as well as evident energy transfer from Bi3+ to Tb3+ within the co-doped BLZO, discussed in detail. Optimal doping concentrations are determined to be 5 mol% for Tb3+ and 0.3 mol% for Bi3+ in BLZO phosphor, with non-radiative transition mechanisms explaining concentration quenching. BLZO:Tb3+ NPs emits green light, while co-doping with Bi3+ shifted to the blue-green region. The optimized phosphor is employed for latent fingerprint (LFP) development on porous, semi-porous, and non-porous surfaces, with clear visualization under 365 nm UV light. The generated fingerprints (FPs) display level I–III ridge features with exceptional sensitivity, selectivity, and contrast. The luminescent hydro-gels exhibit outstanding photo-stability, chemical stability, and long-term durability, making them ideal for anti-counterfeiting (AC) applications. Furthermore, BLZO:Tb3+, Bi3+ NPs demonstrate the ability to mitigate oxidative stress and thrombosis, evidenced by their DPPH scavenging activity and their capacity to normalize stress indicators in Red Blood Cells (RBC) exposed to NaNO2-induced oxidative stress. These NPs also reduce ADP-induced platelet aggregation. Collectively, these results highlight the effective utilization of the optimized phosphor in display devices, advanced forensics, anti-counterfeiting measures, and biomedical applications.

Abstract 14010: Synergistic Influence of Rivaroxaban on Platelets, Inflammation and Coagulation Biomarkers in Patients With CAD and/or PAD on Aspirin Therapy

Background: Cardiovascular benefits of 2.5 mg twice daily rivaroxaban plus aspirin therapy (RIV+ASA) has been demonstrated in patients with arterial diseases. Hypothesis: RIV+ASA is associated with reduced platelet activation and plasma inflammation and coagulation activation markers in patients with CAD and/or PAD who were on ASA. Methods: In this open-label biomarker study, patients on 81 mg/day ASA were randomized to continue ASA or RIV+ASA for 12 weeks. We assessed ADP-, α-thrombin-, and tissue factor-induced platelet aggregation (PA) using conventional aggregometry, platelet-fibrin clot strength (PFCS) by INTEM (intrinsic pathway activator) and EXTEM (extrinsic pathway activator) using thromboelastometry, shear-induced PA by platelet function analyzer-100, D-dimer and fibrinogen using coagulation analyzer, hs-CRP and interleukin-6 using ELISA method at baseline, and four weeks and 12 weeks post-randomization. Results: Data was available in 9 patients with RIV + ASA and ten patients with ASA-only therapy. Most patients were male, Caucasians, obese and older. There were no differences in baseline demographics, medications, and laboratory values between groups, except patients in RIV + ASA group had higher white blood cell counts (p=0.028) and lower baseline 2uM ADP-induced PA (p=0.03). There were no differences in other laboratory measurements between baseline and post-randomization time points within the group or at 4- and 12-week time points between groups, except D-dimer values were significantly lower at 12 weeks (p=0.038) in the RIV + ASA vs. ASA-only group. No significant adverse events were observed. Conclusions: Twelve weeks of rivaroxaban plus aspirin vs. aspirin was associated with similar levels of platelet aggregation, platelet fibrin clot strength, fibrinogen and inflammation markers, and lower d-dimer levels.

Broad-spectrum ginsentides are principal bioactives in unraveling the cure-all effects of ginseng

Stress and illness connection is complex and involves multiple physiological systems. Panax ginsengs, reputed for their broad-spectrum “cure-all” effect, are widely prescribed to treat stress and related illnesses. However, the identity of ginseng's “cure-all” medicinal compounds that relieve stress remains unresolved. Here, we identify ginsentides as the principal bioactives that coordinate multiple systems to restore homeostasis in response to stress. Ginsentides are disulfide-rich, cell-penetrating and proteolytic-stable microproteins. Using affinity-enrichment mass spectrometry target identification together with in vitro, ex vivo and in vivo validations, we show that highly purified or synthetic ginsentides promote vasorelaxation by producing nitric oxide through endothelial cells via intracellular PI3K/Akt signaling pathway, alleviate α1-adrenergic receptor overactivity by reversing phenylephrine-induced constriction of aorta, decrease monocyte adhesion to endothelial cells via CD166/ESAM/CD40 and inhibit P2Y12 receptors to reduce platelet aggregation. Orally administered ginsentides were effective in animal models to reduce ADP-induced platelet aggregation, to prevent collagen and adrenaline-induced pulmonary thrombosis as well as anti-stress behavior of tail suspension and forced swimming tests in mice. Together, these results strongly suggest that ginsentides are the principal panacea compounds of ginsengs because of their ability to target multiple extra- and intra-cellular proteins to reverse stress-induced damages.

Polysaccharide-rich extract of Genipa americana leaves exerts anti-inflammatory effects modulated by platelet mediators

Ethnopharmacological relevanceGenipa americana L. (Rubiaceae) leaves are traditionally used to treat fever, pharyngitis, healing, luxation and bruises. Aim of the studyThis study aimed to investigate the anti-inflammatory effect of the polysaccharide-rich extract of G. americana leaves (PE-Ga) in acute inflammation models and underlying mechanisms associated with platelet activity. Materials and methodsRats received PE-Ga (0.3–3.0 mg/kg; IV) 30 min before injection (IP or SC) of zymosan, serotonin, PGE2, PLA2, PAF or L-arginine, and evaluated in the models of paw edema and acute peritonits. The blockage of plasma serotonin reuptake into platelets was performed with fluoxetine (40 mg/kg; IP). ResultsIn vitro, PE-Ga inhibited ADP-induced platelet aggregation up to 49%. In the edema model, PE-Ga reduced (41%) the time-course of the edema induced by zymosan, mainly the last phase (62%), as well as that induced by PLA2 (32%), PAF (35%), L-arginine (36%), PGE2 (49%) or serotonin (54% AUC); and reversed paw hypernociception induced by PGE2 or serotonin. In the peritonitis model, PE-Ga reversed abdominal hypernociception and reduced leukocyte migration induced by zymosan to blood (38%) and peritoneal cavity (55%), mainly neutrophils (70%). PE-GA also decreased leukocyte rolling (32%) and adhesion (47%), and increased the rolling velocity 2.2-fold. In the peritoneal fluid, PE-Ga reversed P-selectin and reduced total proteins (17%), MDA (40%), NO2−/NO3− (27%), and MPO activity (43%) but increased catalase activity 3.3-fold compared to zymosan. In addition, fluoxetine reversed PE-Ga anti-inflammatory effect on leukocyte migration and adhesion. ConclusionsPE-Ga exerts antiplatelet and anti-inflammatory effects in acute inflammation induced by zymosan, being modulated by P-selectin and platelet serotonin, among other inflammatory mediators.

Anti-thrombotic Effects Mediated by a Novel Dual-Target Peptide Inhibiting Both Platelet Aggregation and Thrombin Activity without Causing Bleeding.

Classical anticoagulants and antiplatelets are associated with high frequencies of bleeding complications or treatment failure when used as single agents. Thrombin plays an important role in the blood coagulation system. GP IIb/IIIa is the central receptor of platelets, which can recognize the Arg-Gly-Asp (RGD) sequence and activate platelets. Molecular simulation and homology modeling were performed to design a novel dual-target anticoagulant short peptide (PTIP ). The activities of PTIP on coagulation and platelet in vitro were analyzed. The antithrombotic activity of PTIP was determined by pulmonary thromboembolism model, ferric chloride injury model and arteriovenous bypass thrombosis model. Bleeding effect and toxicity of PTIP were evaluated. We have constructed a novel dual-target peptide (PTIP) based on the direct thrombin inhibitor peptide (DTIP). PTIP was expressed at high levels in Pichia pastoris. PTIP interfered with thrombin-mediated coagulation and ADP-induced platelet aggregation in vitro. When injected intravenously or subcutaneously, PTIP showed potent and dose-dependent extension of aPTT and PT which were similar to DTIP; but only PTIP was capable of inhibiting platelet aggregation. PTIP (1.0 mg/kg) decelerated thrombosis formation in venous and arterial vessels induced by FeCl3 injury. PTIP (1.0 mg/kg) also prevented deep venous thrombosis and increased the survival rate associated with pulmonary thromboembolism. And PTIP effectively reduced thrombus length in arteriovenous bypass thrombosis model. Moreover, the antithrombotic dose of PTIP could not induce bleeding. These data establish that PTIP represents a novel antithrombotic agent whose effects involve both inhibition of platelet activation and reduction of fibrin generation. And PTIP not only can be used in venous thrombosis and arterial thrombosis, it can also replace the combined treatment of antiplatelet and anticoagulant drugs in thrombotic diseases.

No impact of polymorphism in the phosphodiesterase 5A gene in Cavalier King Charles Spaniels on pimobendan-induced inhibition of platelet aggregation response.

A variant in the canine phosphodiesterase (PDE) 5A gene (PDE5A:E90K) is associated with decreased concentrations of circulating cyclic guanosine monophosphate (cGMP) and response to PDE5 inhibitor treatment. Pimobendan is a PDE inhibitor recommended for medical treatment of certain stages of myxomatous mitral valve disease (MMVD) in dogs. PDE5A:E90K polymorphism attenuates the inhibitory effect of pimobendan on in vitro platelet aggregation and increases basal platelet aggregation in Cavalier King Charles Spaniels (CKCS). Selected clinical variables (MMVD severity, sex, age, hematocrit, platelet count in platelet-rich plasma [PRP], and echocardiographic left ventricular fractional shortening [LV FS]) will not show an association with results. Fifty-two privately owned CKCS with no or preclinical MMVD. Using blood samples, we prospectively assessed PDE5A genotype using Sanger sequencing and adenosine diphosphate-induced platelet aggregation response (area under the curve [AUC], maximal aggregation [MaxA], and velocity [Vel]) with and without pimobendan using light transmission aggregometry. Dogs also underwent echocardiography. Pimobendan inhibited platelet function as measured by AUC, MaxA, and Vel at a concentration of 10 μM (P < .0001) and Vel at 0.03 μM (P < .001). PDE5A:E90K polymorphism did not influence the inhibitory effect of pimobendan or basal platelet aggregation response. The PDE5A:E90K polymorphism did not influence in vitro basal platelet aggregation response or the inhibitory effect of pimobendan on platelet aggregation in CKCS. Dogs with the PDE5A:E90K polymorphism did not appear to have altered platelet function or response to pimobendan treatment.

Optimization of antiplatelet therapy in patients with coronary artery disease and type 2 diabetes mellitus after percutaneous coronary interventions

Abstract Funding Acknowledgements Type of funding sources: None. Background Dual antiplatelet therapy (DAP) with clopidogrel and aspirin after percutaneous coronary interventions (PCI) in patients with chronic coronary syndrome (CCS) are mainly used to prevent stent thrombosis and restenosis. Despite the use of approved doses of the antiplatelet, major adverse cardiac events (MACE) frequently occur in short and mid-term period in patients with type 2 diabetes mellitus (T2DM) and CCS. Aim of the study was to evaluate the efficacy of ticagrelol in patients with CCS and T2DM after elective PCI. Material and Methods The prospective, open label randomized study with 112 patients with CCS and T2DM who admitted for the elective PCI were enrolled in the study from 2018 to 2022 (aged 49-72 years, mean age 59.2±12.2 years, male 52%). Patients were divided into two groups by 56 via open randomization. Group I patients were assigned ticagrelol 90 mg BID after the loading dose of 180 mg ticagrelol along with standard dose of aspirin for 1 year whereas Group II were assigned clopidogrel along with aspirin for 1 year. 20 µmoll ADP induced platelet aggregation was assessed at baseline and after the 12 hours of administering loading dose of antiplatelet. Efficacy and safely were assessed during the follow up in both group of patients. All statistical analysis were performed using STATA software. Results Inhibition of platelet aggregation (IPA) with 20 µmoll ADP at 12 hours was significantly higher in ticagrelol group than clopidogrel group (71.65±14.25% vs. 42.74±18.25%, P&amp;lt;0.001). During the maintenance dose, IPA with 20 µmoll ADP at 48 hours was significantly higher in ticagrelol group than clopidogrel group (68.12±13.27% vs. 45.82±17.54%, P&amp;lt;0.001). PCI bleeding complications were similar in each group and there was not observed any statistically significant changes (P&amp;gt;0.05). During the mean follow-up period ticagrelol group tended to have higher bleeding than clopidogrel group, however they were not observed any statistically significant changes (log-rank test; 0.752). Pertaining to MACE, ticagrelol group tended to have lesser MACE than clopidogrel group, (Mantel–Cox test; P=0.045). 56 ticagrelol treated patients showed that MACE tended to be negatively associated with post PCI bleeding complications (P=0.048). Conclusions Dual antiplatelet therapy with ticagrelol and aspirin is superior than clopidogrel plus aspirin to prevent MACE in patients with chronic coronary syndrome and type 2 diabetes mellitus after elective percutaneous coronary interventions. However, ticagrelol should be used cautiously in patients with gastrointestinal ulcers due to its PCI related bleeding risks.

Association of ADP-Induced Whole-Blood Platelet Aggregation with Serum Low-Density Lipoprotein Cholesterol in Patients with Coronary Artery Disease When Receiving Maintenance Ticagrelor-Based Dual Antiplatelet Therapy.

The degree of platelet inhibition in patients undergoing dual antiplatelet therapy (DAPT) affects cardiovascular outcomes after acute coronary syndromes (ACS) and/or percutaneous coronary intervention. Our aim was to search for correlates of residual ex vivo platelet reactivity and circulating soluble P-selectin (sP-selectin), an index of in vivo platelet activation, in patients being treated by DAPT with ticagrelor. Adenosine diphosphate (ADP)-induced platelet aggregability (by multiple electrode aggregometry) and plasma sP-selectin were estimated in 62 stable post-ACS subjects (46 men and 16 women; mean age: 64 ± 10 years; 30 with type 2 diabetes (T2DM)) undergoing maintenance DAPT with ticagrelor and aspirin. These patients did not exhibit heart failure or other relevant coexistent diseases except for properly controlled T2DM, mild renal insufficiency, and hypertension. We also assessed this in 64 subjects on clopidogrel-based DAPT matched for age, sex, and T2DM status. ADP-induced platelet aggregation was below the optimal levels (190-460 arbitrary units (AU) * min) in most patients receiving ticagrelor-based DAPT, especially in those with below-median (<1.9 mmol/L) serum concentrations of low-density lipoprotein cholesterol (LDL-c) (128 ± 61 vs. 167 ± 73 AU * min for below-median and above-median LDL-c, respectively, p = 0.025). In contrast, platelet reactivity did not differ by LDL-c on clopidogrel-based DAPT (246 ± 101 vs. 268 ± 108 AU * min for below-median and above-median LDL-c, respectively, p > 0.4). Plasma sP-selectin was found to be unrelated to serum LDL-c when receiving DAPT with ticagrelor (p > 0.4) or clopidogrel (p > 0.8). In conclusion, our preliminary observational study suggests the association of lower residual ex vivo platelet aggregability with better LDL-c control in patients undergoing ticagrelor-based maintenance DAPT, which does not appear to be reflected by plasma sP-selectin. Whether the serum LDL-c level should be considered among the factors affecting the degree of platelet inhibition for those treated with ticagrelor-based DAPT needs to be investigated in larger studies.

Biological activities of Vipegrin, an anti-adhesive Kunitz-type serine proteinase inhibitor purified from Russell's viper venom

Vipegrin is a 6.8 kDa Kunitz-type serine proteinase inhibitor purified from Russell's viper (Vipera russelii russelii) venom. Kunitz-type serine proteinase inhibitors are non-enzymatic proteins and are ubiquitous constituents of viper venoms. Vipegrin could significantly inhibit the catalytic activity of trypsin. It also posseses disintegrin-like properties and could inhibit collagen and ADP-induced platelet aggregation in a dose-dependent manner. Vipegrin is cytotoxic to MCF7 human breast cancer cells and restricts its invasive property. Confocal microscopic analysis revealed that Vipegrin could induce apoptosis in MCF7 cells. Vipegrin disrupts cell to cell adhesion of MCF7 cells through its disintegrin-like activity. It also causes disruption of attachment of MCF7 cells to synthetic (poly L-lysine) and natural (fibronectin, laminin) matrices. Vipegrin did not cause cytotoxicity on non-cancerous HaCaT, human keratinocytes. The observed properties indicate that Vipegrin may help the development of a potent anti-cancer drug in future.

#4878 STUDYING THE EFFECTIVENESS OF PRASUGREL AND CLOPIDOGEL IN PATIENTS WITH CHRONIC LOWER LIMB ISCHEMIA WITH STAGE 2 CKD

Abstract Background and Aims To compare the clinical and rheological efficacy of prasugrel and clopidogrel in patients with chronic lower limb ischemia with stage 2 chronic kidney disease. According to statistics, in Europe, peripheral arterial disease is common in more than 40 million Europeans. According to the developed tactics, not only stroke should be recognized as a serious, life-threatening condition, but other peripheral vascular diseases can lead to disability and death. Methods The study included 101 patients with critical lower limb ischemia of atherosclerotic origin. The mean age of the patients was 51.51±8.33 years. As a control group, 20 healthy volunteers (mean age 53.90 ± 9.05 years) were examined without signs of pathology of the cardiovascular system, including those of a vegetative nature. All patients included in the study were hospitalized in the Department of Interventional Cardiology of the Republican Specialized Scientific and Practical Center for Therapy and Medical Rehabilitation, Tashkent city. Results In 94 patients (93.07%), CLCI was accompanied by hemodynamically significant multifocal atherosclerotic lesions. The first place in frequency of combined lesions was occupied by the coronary vessels, the second place - by the arteries of the brachiocephalic basin. 82 patients (81.19%) had previously suffered arterial occlusion, also most often in the form of acute myocardial infarction, somewhat less often - acute cerebrovascular accident. 47 patients (46.53%) underwent revascularization earlier, mainly coronary artery stenting, coronary artery bypass grafting, carotid endarterectomy. 8 patients (7.92%) underwent revascularization of the contralateral leg. The study studied spontaneous (SAT) and ADP-induced platelet aggregation. In the CG, SAT was noted only in 50% of cases and in all patients of the CLCI group. After comparing the results in the groups of patients with CLCI and representatives of the CG, in whom SAT was noted, it was found that both the rate and degree of SAT in the group of patients were significantly higher than in healthy individuals (2.95±0.59% versus 0.55± 0.21% and 6.05±1.54% versus 1.24±0.21%, respectively, p&amp;lt;0.001 significance of the intergroup difference of both parameters). All patients due to CINC underwent endovascular revascularization of the affected leg. After the procedure, patients were prescribed an antiplatelet agent at a maintenance dose (prasugrel 10 mg/day, clopidogrel 75 mg/day). After 3 months, a control examination was carried out, during which the dynamics of platelet aggregation activity was studied. It was found that the indicators of CAT and ADP induced aggregation decreased by 22-37%. During the test, patients with resistance to antiplatelet agents were identified - in whom the decrease in the degree of ADP5 induced aggregation was less than 20%. Such resistance was found in 19 patients: 1 patient in the prasugrel group (1.69%) and 18 patients in the clopidogrel group (42.86%, chi square = 27.00, p&amp;lt;0.001). Isolation of patients with normal and reduced response to the loading dose of clopidogrel revealed some differences (Table 3.3). So, already initially in this group of patients, the degree of ADP5-induced aggregation was lower than in the group of patients with an antiplatelet response of more than 20%. After the application of a loading dose of clopidogrel, differences in relative dynamics were noted only in terms of the degree of ADP%-induced aggregation (p&amp;lt;0.001). Conclusions Thus, the present study revealed that in patients with CLCI, there is a significant activation of CAT and an increase in the aggregation response to the introduction of high doses of the inducer of ADP5 aggregation. The loading dose of antiplatelet agents contributed to a significant decrease in platelet aggregation activity after 2 hours with a large effect of prasugrel. Chronic antiplatelet therapy led to a decrease in the rate and degree of aggregation, both spontaneous and ADP-induced, a decrease in the endogenous ADP release response, also with a great effect in patients taking prasugrel.