P2Y Receptors Research Articles

Purinergic signaling through the P2Y2 receptor regulates osteocytes' mechanosensitivity.

Osteocytes' response to dynamic loading plays a crucial role in regulating the bone mass but quickly becomes saturated such that downstream induction of bone formation plateaus. The underlying mechanisms that downregulate osteocytes' sensitivity and overall response to loading remain unknown. In other cell types, purinergic signaling through the P2Y2 receptor has the potential to downregulate the sensitivity to loading by modifying cell stiffness through actin polymerization and cytoskeleton organization. Herein, we examined the role of P2Y2 activation in regulating osteocytes' mechanotransduction using a P2Y2 knockout cell line alongside conditional knockout mice. Our findings demonstrate that the absence of P2Y2 expression in MLO-Y4 cells prevents actin polymerization while increasing the sensitivity to fluid flow-induced shear stress. Deleting osteocytes' P2Y2 expression in conditional-knockout mice enabled bone formation to increase when increasing the duration of exercise. Overall, P2Y2 activation under loading produces a negative feedback loop, limiting osteocytes' response to continuous loading by shifting the sensitivity to mechanical strain through actin stress fiber formation.

Direct IL-6 inhibition prevents arterial thrombosis by reducing collagen-mediated platelets activation

Abstract Introduction Interleukin 6 (IL-6) has a pivotal role in atherothrombosis. Yet, targeting IL-6 to prevent atherothrombotic events still requires validation of efficacy and safety. The recent phase 2 RESCUE trial reported that direct inhibition of IL-6 ligand by the monoclonal antibody (mAb) Ziltivekimab is safe in patients with elevated cardiovascular risk. Purpose This project investigated the effects of direct IL-6 inhibition on arterial thrombosis, and assessed the underlying cellular mechanisms. Methods Three month old C56Bl/6 male mice received very-low dose LPS i.p. for 4 weeks. During the last week they were randomized to receive in addition either anti-mouse IL-6 mAb 200 μg i.p. every other day or IgG1 isotype control. Then thrombosis of left common carotid artery (LCCA) was induced by laser injury under anesthesia. Platelets of treated mice were isolated and stimulated with either adenosine di-phosphate (ADP), collagen-related peptide (CRP) or thrombin receptor activating peptide (TRAP). Platelets activation was measured by flow-cytometry, as expression of P-selectin and JON/A.The effect of direct IL-6 inhibition was confirmed in patients with stable coronary artery disease (sCAD) by ex-vivo incubation of isolated platelets with either anti-human IL-6 mAb 1.5 μg/mL or IgG1 isotype control. Platelet activation was measured by flow-cytometry, as expression of P-selectin. Results Mice treated with anti-IL6 antibody displayed a significantly longer time-to-occlusion after the LCCA (Figure 1), without any significant difference in coagulation parameters. After stimulation with CRP, platelets were significantly activated in control mice, but not in mice treated with anti-IL6 mAb. Similarly, activation of isolated platelets from patients with sCAD was significantly reduced (Figure 2) by the ex-vivo treatment with anti-IL6 mAb. Conclusion The direct inhibition of IL-6 reduces platelets reactivity to collagen, thereby blunting arterial thrombosis upon endothelial damage. These results provide a potential mechanism to explain the reduction of cardiovascular risk associated to direct IL-6 inhibition. Conclusion The direct inhibition of IL-6 reduces platelets reactivity to collagen, thereby blunting arterial thrombosis upon endothelial damage. These results provide a potential mechanism to explain the reduction of cardiovascular risk associated to direct IL-6 inhibition.Figure 1Figure 2

Epidemiology of recurrent myocardial infarction in the reperfusion era

Abstract Introduction During the past decades, the incidence, management, and outcomes of myocardial infarction (MI) have improved considerably.(1-4) However, the characteristics and outcomes of patients who experience a recurrent MI are sparsely described. Purpose This study aimed to analyse the epidemiology and temporal trends of recurrent MI during the reperfusion era. Methods A nationwide registry-based cohort study was conducted, including all hospital admissions for recurrent MI in Denmark during 2000 to 2020. Descriptive statistics were used to analyse changes in patient characteristics and management. Survival analyses, taking competing risks into account when relevant, and multivariable Cox proportional hazards models adjusted for sex, age, comorbidities, and pre-recurrent MI pharmaceutical treatment were used to analyse the outcomes of interest: all-cause mortality, hospitalisation for heart failure (HHF), and additional recurrent MI. Results A total of n=55,722 admissions for recurrent MI between 2000 and 2020 were included. Median age at admission was 73 years, 68.0% were male, and 32.9% were patients with a 3rd or more recurrent MI. Between 2000-02 (n=9,490) and 2018-20 (n=5,520), patients admitted with a recurrent MI had an increased prevalence of comorbidities such as diabetes, chronic kidney disease, and cancer (Condensed Table 1). Likewise, the use of guideline directed management at the time of recurrent MI increased during the study period: percutaneous coronary intervention (PCI) from 12.8% to 47.2%, coronary angiography (CAG) from 21.8% to 68.0%, statins from 30.5% to 74.2%, and adenosine diphosphate (ADP) receptor inhibitors from 8.2% to 41.8%. Statistically significant linear calendar time trends were observed for all three outcomes (Figure 1). Between 2000-02 and 2018-20 (Figure 2), the absolute 1-year risk of mortality declined from 31.6% to 16.0% (adjusted hazard ratio [aHR]: 0.46 [95% CI: 0.43-0.50]). The absolute 1-year risk of an additional recurrent MI declined from 13.9% to 6.2% (aHR: 0.38 [0.34-0.43]). The absolute 1-year risk of HHF increased from 8.8% in 2000-02 to 10.5% in 2009-11 (aHR: 1.09 [0.99-1.21]), before declining to 7.4% in the final calendar year period (aHR: 0.75 [0.66-0.84]). Interpretation and conclusion Despite remarkable advances in the management and outcomes of patients experiencing recurrent MI during the reperfusion era, this remains a vulnerable, high-risk population. Special attention is warranted regarding the optimization of guideline directed care and prevention of heart failure following a recurrent MI.Figure 1Figure 2 & Condensed Table 1

Association of ticagrelor vs clopidogrel with net adverse clinical events in NSTEMI patients with mild thrombocytopenia

Abstract Backgrounds: Guidelines currently recommend aspirin plus ticagrelor as the preferred dual antiplatelet therapy (ADPT) for non-ST-elevation myocardial infarction (NSTEMI). However, there are no established recommendations for managing NSTEMI patients with mild thrombocytopenia, defined as a platelet count of 100~150×109/L. Purpose This study aims to investigate the association between ticagrelor and clopidogrel with ischemic and hemorrhagic events in NSTEMI patients with a platelet count of 100~150×109/L. Methods A retrospective cohort study was conducted using data from the Health and Medical Big Data Super Platform from January 2010 to June 2023. The study included NSTEMI patients with a platelet count of 100~150×109/L who received DAPT consisting of aspirin and a P2Y12 receptor antagonist (eithor clopidogrel or ticagrelor). Patients were followed up for at least one year. The inverse probability of treatment weighting (IPTW) approach based on propensity score was used to balance the observed confounders between treatments. The primary endpoint was net adverse events (NACE) at 1 year, composed of ischemic events (recurrent myocardial infarction or ischemic stroke), Bleeding Academic Research Consortium (BARC) classification ≥ 3, and cardiac death. Secondary outcomes included cardiac death, recurrent myocardial infarction and, ischemic stroke. Results The study cohort comprised 2969 participants, with a median age of 72 years and 29.2.0% female. After adjustment using inverse probability of treatment weighting, ticagrelor and clopidogrel showed similar rates of NACE (aHR, 0.84; 95%Cl, 0.58-1.21). Cardiac death (aHR, 0.99; 95%Cl, 0.54-1.83) and ischemic stroke (aHR, 0.94; 95%Cl, 0.49-1.81) did not significantly differ between the two groups. However, ticagrelor was associated with a lower rate of recurrent myocardial infarction (aHR, 0.44; 95%Cl, 0.21-0.93). Conclusion In routine clinical practice, among NSTEMI patients with a platelet count of 100~150×109/L, ticagrelor, did not showed a significant difference in the risk of NACE at 1 year compared with clopidogrel. However, ticagrelor was associated with a lower rate of recurrent myocardial infarction. Further research is warranted to confirm the this conclusion.

Association of ticagrelor vs clopidogrel with net adverse clinical events in patients with mild thrombocytopenia undergoing PCI

Abstract Backgrounds Current guidelines recommend aspirin plus ticagrelor as the preferred dual antiplatelet therapy (DAPT) for managing ST-elevation myocardial infarction (STEMI). However, there is a lack of consensus or guidelines to direct clinicians on managing patients with mild thrombocytopenia, defined as a platelet count of 100~150×109/L, undergoing percutaneous coronary intervention (PCI). Purpose This study aims to investigate the association between ticagrelor and clopidogrel with ischemic and hemorrhagic events for patients with mild thrombocytopenia undergoing PCI. Methods A retrospective cohort study of patients with mild thrombocytopenia undergoing PCI who received DAPT consisting of aspirin and a P2Y12 receptor antagonist (includinig clopidogrel or ticagrelor) was conducted using Health and Medical Big Data Super Platform from January 2010 to June 2023. All patients meeting the criteria were included in the analysis, with a follow-up of at least one year. Propensity Score Matching (PSM) was performed to equalize the effects of following characteristics: age, sex, hypertension, diabetes, dyslipidemia, stroke, atrial fibrillation, Killip class, percutaneous coronary intervention (PCI), beta-blockers, statins, calcium channel blockers (CCB), angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (ACEI or ARB), angiotensin receptor-neprilysin inhibitor (ARNI), diuretic, organic nitrates, and oral anticoagulation. The primary endpoint was net adverse clinical events (NACE) at 1 year, composed of ischemic events (recurrent myocardial infarction or ischemic stroke), Bleeding Academic Research Consortium (BARC) classification ≥ 3, and cardiac death. Secondary outcomes included the components of NACE. Results A total of 3647 patients met the inclusion criteria, with 2684 receiving aspirin plus clopidogrel and 963 receiving aspirin plus ticagrelor, matched by a 1:3 ratio using the PSM method. Demographic characteristics were well balanced between the clopidogrel and ticagrelor groups. The 1-year risk of NACE did not significantly differ between ticagrelor and clopidogrel (11.1% vs. 8.4%, p=0.370). Similarly, there was no significant difference in the risk of cardiac death (7.3% vs. 4.2%, p=0.720), recurrent myocardial infarction (9.3% vs. 5.8%, p=0.550), ischemic stroke (8.8% vs. 6.7%, p=0.055), or BARC type ≥ 3 bleeding (7.9% vs. 4.5%, p=0.990). Conclusion In routine clinical practice, among patients with a platelet count of 100~150×109/L undergoing PCI, ticagrelor compared with clopidogrel was not associated with a significant difference in the risk of NACE at 1 year. Further research is warranted to assess whether ticagrelor is more effective than clopidogrel in this setting, considering potential unmeasured confounders.

Comparative discontinuation and non-bleeding side effects of Clopidogrel, Prasugrel and Ticagrelor in patients with acute coronary syndromes; a Network Meta-analysis of Randomized Controlled Trials

Abstract Background P2Y12 receptor inhibitors are highly effective treatment options following ACS. However, premature discontinuation compromises their effectiveness. Although extensive literature exists, the clinical assessment of their adherence remains controversial, requiring definitive investigation. Purpose To evaluate treatment discontinuation and non-bleeding adverse effects associatedwith platelet P2Y12 receptor inhibitors in individuals post-ACS through network meta-analysis. Methods Data Sources: MEDLINE, Embase, Cochrane, and clinicaltrials.gov to May 2021 and later updated to October 2022. Study Selection and Outcomes: Reviewers identified RCTs that enrolled patients post-ACS taking Clopidogrel, Ticagrelor, and Prasugrel. Exclusions included non-ACS indications, anticoagulation therapy, observational studies, and crossover designs. The primary outcomesincludedoverall treatment discontinuation, treatment discontinuation attributed to side effects, and dyspnea. Secondary outcomes included bradycardia and atrial fibrillation. Data Extraction and Synthesis:This network meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, employing frequentist random-effects models. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework was utilized to assess the certainty of evidence. Results With 139,343 participants in 32 RCTs, the overall treatment discontinuation rate across all studies was 16.57% out of a total of 137,897 participants. Ticagrelor was associated with increased risk for overall treatment discontinuation compared to Clopidogrel (RR, 1.34; 95% CI, 1.19 to 1.49; P<0.0001), Prasugrel (RR, 1.23; 95% CI, 1.07 to 1.41; P=0.0031) and placebo (RR, 1,40; 95% CI, 1.19 to 1.65; P<0.0001). In compatibility to overall treatment discontinuation, Ticagrelor was associated with increased risk for treatment discontinuation due to side effects compared to Clopidogrel (RR, 1.80; 95% CI, 1.36 to 2.38; P<0.0001), Prasugrel (RR, 1.49; 95% CI, 1.06 to 2.10; P=0.0216) and placebo (RR, 1.85; 95% CI, 1.21 to 2.83; P=0.0044). Ticagrelor, Prasugrel and Clopidogrel were associated with an increased risk for dyspnea in comparison to placebo (RR, 2.86; 95% CI, 2.57 to 3.17; P<0.0001; RR, 1.61; 95% CI, 1.35 to 1.91; P<0.0001; RR, 1.60; 95% CI, 1.41 to 1.82; P<0.0001) respectively. Ticagrelor was associated with increased risk for dyspnea compared to Clopidogrel (RR, 1.78; 95% CI, 1.65 to 1.92; P<0.0001) and prasugrel (RR, 1.78; 95% CI, 1.55 to 2.05; P<0.0001). Conclusions The findings of this study suggest that Ticagrelor presents the highest risk for premature discontinuation compared to Clopidogrel and Prasugrel. Additionally, P2Y12 receptor inhibitors, in general, are notably associated with dyspnea, with Ticagrelor showing the highest risk. These results provide health professionals with valuable information for making treatment decisions in patients post-ACS.NMA netgraphsNMA of Overall treatment discontinuation

Real-world evidence supports superior efficacy of prasugrel over ticagrelor in individuals with acute coronary syndrome

Abstract Background In patients with acute coronary syndrome (ACS) undergoing invasive treatment, ticagrelor and prasugrel are guideline-recommended P2Y12 receptor inhibitors. Preference for one of the two drugs is under debate although the ISAR-REACT5 trial revealed advantages for prasugrel. This real-world data study evaluated the efficacy and safety of ticagrelor versus prasugrel in individuals with ACS undergoing invasive treatment by emulating a target trial analogous to ISAR-REACT5. Methods Following the Population, Intervention, Comparator, Outcome, and Timing (PICOT) framework, within a German health claims database, we adapted the inclusion and exclusion criteria from ISAR-REACT5 and identified a 1:1 propensity score-matched cohort with ACS being treated after hospital discharge with either ticagrelor or prasugrel (n=9,380, each). End points were defined as in ISAR-REACT5 at 1-year follow-up. Additionally, subgroup analyses of individual ACS components ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina (UA) were conducted. Results The primary composite end point occurred in 9.2% of ticagrelor and 7.4% of prasugrel treated individuals (hazard ratio 1.22; 95% confidence interval 1.10-1.35). Likewise, the secondary end points MI and stroke occurred significantly more often in the ticagrelor arm. All-cause mortality, stent thrombosis, and the safety end point bleeding revealed no significant differences. Subgroup analysis revealed superiority for prasugrel particularly in individuals with STEMI. Statistically, test results and hazard ratios of this real-world data study were in agreement with the findings of ISAR-REACT5. Conclusions With over four times the cohort size of ISAR-REACT5, this study indicates superior efficacy of prasugrel over ticagrelor in individuals with ACS undergoing invasive strategy.Cumulative incidence of primary endpointGraphical abstract

Is the female sex a risk factor for heart failure after myocardial infarction?

Abstract Background In previous observations, female sex was associated with heart failure after myocardial infarction (MI). However, women were older and had more risk factors and were not treated the same as men. Purpose Our aim was to investigate the differential impact of sex on heart failure (including cardiogenic shock) and outcome in a propensity score matched population with MI who had undergone percutaneous coronary intervention (PCI) and the association between sex, heart failure and long-term mortality. Methods Data from 3624 (30.6% women) MI patients who underwent PCI at our institution were analyzed. Propensity-score matching analysis was performed to adjust for differences in baseline characteristics between men and women. After propensity matching, the sample comprised 2170 patients (1085 women and 1085 men). Heart failure was defined by clinical criteria (bilateral pulmonary rales, S3 gallop, edema or cardiogenic shock) and/or pulmonary edema on chest X-ray and/or ejection fraction <30%. The data were analyzed using descriptive statistics. The median follow-up time was 27 months (25th, 75th percentile: 9,48). Results In hospital, 329 (16.4%) patients developed heart failure, with a similar incidence in men and women (156(15.5%) vs. 173(17.2%);p=0.33) (Figure 1). Furthermore, female sex was not associated with heart failure either univariately (OR 1.13;95%CI 0.89-1.43;p=0.31) or after adjustment for confounding factors (aOR 1.27;95% CI 0.96-1.66;p=0.093). Age, hypertension, hyperlipidemia, ST- elevation MI, and P2Y12 receptor inhibitors were associated with heart failure. We followed the patients for up to six years. At the end of the observation period, 330(16.4%) patients had died. The mortality rate was similar in both sexes (159(15.8%) men died compared to 171(17.0%) women; p=0.51) (Figure 2). In addition, sex was not associated with long-term mortality (aHR 1.11;95%CI 0.88-1.40;p=0.38) after adjusting for confounders. In-hospital heart failure was independently associated with long-term mortality (aHR 2.64;95%CI 2.04-3.41;p<0.0001). Hyperlipidemia, age, ST- elevation MI, radial access, P2Y12 receptor inhibitor and GFR were also associated with long-term mortality. Conclusions Our results suggest that sex itself is not associated with heart failure after MI when women are treated similarly to men, have similar risk factors, and are of similar age. It is more likely that women are more frequently affected by heart failure because they are older, have more risk factors, are less likely to be revascularized, and are less likely than men to be treated with guideline-recommended therapy,Heart failure in men and womenLong-term all-cause mortality

Phase I results of both IV and oral administration for CG-0255: a novel fast-acting antiplatelet drug with a new activation pathway

Abstract Clopidogrel is an extremely widely used antiplatelet drug, but with serious shortcomings. It is a prodrug that depends critically on liver CYP oxidation enzyme CYP2C19 for activation to its active metabolite H4. However, large fractions of world population carry loss of function CYP2C19 alleles, ranging from a low ~21% in Latino to a strikingly high ~59% in east Asian population. Known as clopidogrel resistance, US FDA added a black box warning to clopidogrel label. Despite this issue, routine CYP2C19 screening for clopidogrel patients is not performed, putting many patients at risk. Clopidogrel is also slow to take effect and not amenable for IV formulation, limiting its clinical use in emergency. To overcome these issues, we have invented a novel antiplatelet drug CG-0255, which is the world’s first thioester prodrug with a new activation pathway. CG-0255 has been designed to require only abundantly present and widely distributed carboxylesterases for metabolizing to its active metabolite, which is identical to clopidogrel active metabolite H4 generated through CYP metabolism. Thus, CG-0255 completely bypasses the CYP metabolism and overcomes clopidogrel resistance. In addition, CG-0255 has a much faster onset of action and high solubility in water and has been formulated for both IV and oral administration. Here we report the results of an open label phase I study of CG-0255 oral tablets to assess safety, tolerability, pharmacodynamics (PK), and pharmacokinetics (PD: inhibition of platelet aggregation, IPA) in healthy volunteers. It was a single dose escalation study, 4 cohorts with 6 participants each given CG-0255 oral tablets at doses ranging from 2 to 10 mg. Clopidogrel was the positive control and given at 300 mg. Blood samples for PK/PD analysis were collected pre-dosing and at various time points post dosing. VerifyNow was used for IPA measurement. CG-0255 is generally safe and well tolerated. PK analysis shows fast and consistent conversion of CG-0255 to active metabolite H4. PD results indicate that CG-0255 IPA is dose-dependent, easily matching or surpassing that of clopidogrel 300 mg for all doses. At the highest 10 mg dose, CG-0255 IPA reaches over 90% in less than 30 minutes, well above that of clopidogrel. In addition, CG-0255 IPA shows minimum individual variations, and the antiplatelet effect is long lasting due to its irreversible binding to the P2Y12 receptor. These results are consistent with our earlier reported Phase I results for CG-0255 IV injection. In conclusion, CG-0255 is a novel, fast-acting and long-lasting antiplatelet drug. It shares identical metabolite H4 with clopidogrel but relies only on carboxylesterases for activation, overcoming the resistance and other issues associated CYP-based oxidation metabolism. As the only antiplatelet drug available for both IV and oral administrations, CG-0255 fills unmet medical needs and will greatly benefit patients and medical community.

Association of ticagrelor vs clopidogrel with net adverse clinical events in STEMI patients with mild thrombocytopenia

Abstract Backgrounds Current guidelines advocate for aspirin plus ticagrelor as the preferred dual antiplatelet therapy (DAPT) for ST-elevation myocardial infarction (STEMI). However, there is a lack of consensus or guidelines to direct clinicians on managing STEMI patients with mild thrombocytopenia, defined as a platelet count of 100~150×109/L. Purpose This study aims to investigate the association between ticagrelor and clopidogrel with ischemic and hemorrhagic events in STEMI patients with a platelet count of 100~150×109/L. Methods A retrospective cohort study was conducted using Health and Medical Big Data Super Platform from January 2010 to June 2023.The study included STEMI-patients with a platelet count of 100~150×109/L who received DAPT consisting of aspirin and a P2Y12 receptor antagonist (either clopidogrel or ticagrelor) All STEMI patients with a platelet count of 100~150×109/L were included in the analysis with a follow-up of at least one year. The inverse probability of treatment weighting (IPTW) approach based on propensity score was utilized to balance observed confounders between treatments. The primary endpoint was net adverse events (NACE) at 1 year, including ischemic events (recurrent myocardial infarction or ischemic stroke), Bleeding Academic Research Consortium (BARC) classification ≥ 3, and cardiac death. Secondary outcomes were cardiac death, recurrent myocardial infarction, and ischaemic stroke. Results The study cohort consisted 2941 participants with median age of 69 years, and 21.0% were female. Following adjustment using the inverse probability of treatment weighting, ticagrelor and clopidogrel demonstrated similar NACE (aHR, 0.86; 95%CI, 0.60-1.23). Cardiac death (aHR, 0.69; 95%CI, 0.36-1.31), recurrent myocardial infarction (aHR, 0.94; 95%CI, 0.50-1.78), and ischaemic stroke (aHR, 0.62; 95%CI, 0.34-1.14) did not significantly differ between the two groups. Conclusion In routine clinical practice, among STEMI patients with a platelet count of 100~150×109/L ticagrelor compared with clopidogrel, was not associated with a significant difference in the risk of NACE at 1 year. Further research is warranted to assess whether ticagrelor is more effective than clopidogrel in this particular patient population.

Isosmotic Striction of Rat Aorta Smooth Muscle Cells During Activation of Purinergic Receptors: Role of Chlorine Transport

We studied the effect of the purinergic signaling system and Cl-transporters on vascular smooth muscle cells (SMC) isosmotic striction that occurs when osmotic pressure is normalized after prolonged incubation in a hypoosmotic medium. The study was performed with the method of myography on endothelium-denuded ring segments of the male Wistar rats aorta. Isosmotic striction was induced by placing the vascular segments in normosmotic Krebs solution containing 120 mM NaCl after a 40-minute incubation in a hyposmotic Krebs solution containing 40 mM NaCl. Purinergic receptors were activated by adenosine 5'-triphosphate (ATP, 500 μM) as nonselective P2X and P2Y receptor agonist, and uridine 5'-triphosphate (UTP, 500 μM) as selective P2Y receptor agonist. ATP and UTP eliminated the transient nature of the aorta SMC isosmotic striction without affecting its amplitude. Pretreatment of vascular segments with ATP and UTP during incubation in a hyposmotic solution completely suppressed the development of isosmotic striction in the presence of ATP or UTP, but did not affect isosmotic striction without activators of purinergic receptors. The inhibitor of Na+, K+, 2Cl--cotransport (NKCC) bumetanide (100 μM) abolished isosmotic striction in the presence of ATP, but not UTP, but restored its transient character. A non-selective blocker of Cl– channels and Cl–, HCO3– exchanger DIDS (100 μM) suppressed the development of isosmotic striction both in the presence of ATP and UTP. The potassium channel blocker tetraethylammonium (10 mM) potentiates the constrictor action of UTP on isosmotic striction. We suppose purinergic receptors eliminate the transient isosmotic striction by activating Cl– currents through activation of P2Y receptors. The mechanism of interaction between the purinergic signaling system and Cl– transport during changes in cell volume requires further study.

Thromboelastography with Platelet Mapping to Optimize Surgical Timing in Coronary Artery Bypass Grafting Patients on P2Y12 Receptor Blockers Therapy.

An increasing number of patients attending coronary artery bypass grafting (CABG) receive preoperative antiplatelet drugs (acetylsalicylic acid, clopidogrel, prasugrel, ticagrelor). The optimal assessment of preoperative platelet function is the aim of this study for a shorter surgical timing in patients undergoing elective coronary artery bypass grafting. This study was performed on patients presenting for first-time isolated CABG on therapy with an P2Y12 receptor blockers loading dose (clopidogrel [300 mg] or prasugrel [60 mg] or ticagrelor [180 mg]) or P2Y12 receptor blockers maintenance therapy at least for five days (clopidogrel [75 mg once daily], prasugrel [10 mg once daily], ticagrelor [90 mg twice daily]). All patients received simultaneously acetylsalicylate acid (100 mg daily). Exclusion criterion was emergency CABG regardless of preoperative antiplatelet and anticoagulant therapy. All patients' data were recorded in an Excel® file and analyzed using RStudio® software. Forty-eight consecutive adult patients presenting for CABG were enrolled. Preoperative thromboelastography-platelet mapping showed platelet resistance to P2Y12 blockers receptor - 25% for clopidogrel (6/24), 33% for ticagrelor (6/18), 33% for prasugrel (2/6), and this data was useful to obtain a shorter CABG waiting time in comparison with current guidelines (2.7 vs. five days for clopidogrel, 2.5 vs. five days for ticagrelor, 3.3 vs. seven days for prasugrel). Preoperative thromboelastography-platelet mapping is helpful to detect harmful P2Y12 receptor blockers resistance and to minimize CABG waiting time avoiding unnecessary and life-threatening delays.

Exploring P2X7 receptor antagonism as a therapeutic target for neuroprotection in an hiPSC motor neuron model.

ATP is present in negligible concentrations in the interstitium of healthy tissues but accumulates to significantly higher concentrations in an inflammatory microenvironment. ATP binds to 2 categories of purine receptors on the surface of cells, the ionotropic P2X receptors and metabotropic P2Y receptors. Included in the family of ionotropic purine receptors is P2X7 (P2X7R), a non-specific cation channel with unique functional and structural properties that suggest it has distinct roles in pathological conditions marked by increased extracellular ATP. The role of P2X7R has previously been explored in microglia and astrocytes within the context of neuroinflammation, however the presence of P2X7R on human motor neurons and its potential role in neurodegenerative diseases has not been the focus of the current literature. We leveraged the use of human iPSC-derived spinal motor neurons (hiPSC-MN) as well as human and rodent tissue to demonstrate the expression of P2X7R on motor neurons. We extend this observation to demonstrate that these receptors are functionally active on hiPSC-MN and that ATP can directly induce death via P2X7R activation in a dose dependent manner. Finally, using a highly specific P2X7R blocker, we demonstrate how modulation of P2X7R activation on motor neurons is neuroprotective and could provide a unique pharmacologic target for ATP-induced MN death that is distinct from the role of ATP as a modulator of neuroinflammation.

Impact of Ticagrelor vs. Clopidogrel in Patients With Acute Coronary Syndrome Undergoing Left Main Percutaneous Coronary Intervention

Abstract Objective: There is limited evidence regarding the choice of P2Y12 receptor inhibitors as a component of dual antiplatelet therapy (DAPT) in patients with left main (LM) disease undergoing percutaneous coronary intervention (PCI). This study aimed to evaluate long-term clinical outcomes of ticagrelor- vs. clopidogrel-based DAPT strategy in acute coronary syndrome (ACS) patients undergoing LM PCI. Methods: This is a post-hoc analysis from a prospective, single-center, real-world PCI registry. A total of 1,163 patients discharged post-ACS who underwent LM PCI and received ticagrelor or clopidogrel between March 2016 and March 2019 were included in the study. The primary endpoint was ischemic events at 12 months, including cardiac death, myocardial infarction, or stroke. Secondary outcomes included all-cause death and Bleeding Academic Research Consortium types 2, 3, and 5, and types 3 and 5 bleeding. Propensity score matching was used to adjust for bias due to confounders between the 2 groups. Results: The ticagrelor and clopidogrel groups comprised 529 (45.49%) and 634 (54.51%) patients, respectively. During the follow-up period, ticagrelor significantly reduced the rate of ischemic events compared to clopidogrel before (1.32% (7/529) vs. 3.63% (23/634), P = 0.0136) and after propensity score matching (1.41% (6/425) vs. 4.00% (17/425), P = 0.0201). The rates of all-cause death, Bleeding Academic Research Consortium-defined type 2, 3, and 5 bleeding, and type 3 and 5 bleeding were similar between the ticagrelor group and clopidogrel group before or after propensity score matching adjustment (all P > 0.05). Conclusion: Among patients with ACS undergoing LM PCI, ticagrelor use was associated with ischemic events benefit without excessive risk of bleeding at 12 months compared with clopidogrel.

Modification of Neural Circuit Functions by Microglial P2Y6 Receptors in Health and Neurodegeneration.

Neural circuits consisting of neurons and glial cells help to establish all functions of the CNS. Microglia, the resident immunocytes of the CNS, are endowed with UDP-sensitive P2Y6 receptors (P2Y6Rs) which regulate phagocytosis/pruning of excessive synapses during individual development and refine synapses in an activity-dependent manner during adulthood. In addition, this type of receptor plays a decisive role in primary (Alzheimer's disease, Parkinson's disease, neuropathic pain) and secondary (epilepsy, ischemic-, mechanical-, or irradiation-induced) neurodegeneration. A whole range of microglial cytokines controlled by P2Y6Rs, such as the interleukins IL-1β, IL-6, IL-8, and tumor necrosis factor-α (TNF-α), leads to neuroinflammation, resulting in neurodegeneration. Hence, small molecular antagonists of P2Y6Rs and genetic knockdown of this receptor provide feasible ways to alleviate inflammation-induced neurological disorders but might also interfere with the regulation of the synaptic circuitry. The present review aims at investigating this dual role of P2Y6Rs in microglia, both in shaping neural circuits by targeted phagocytosis and promoting neurodegenerative illnesses by fostering neuroinflammation through multiple transduction mechanisms.

In vivo imaging in mouse spinal cord reveals that microglia prevent degeneration of injured axons

Microglia, the primary immune cells in the central nervous system, play a critical role in regulating neuronal function and fate through their interaction with neurons. Despite extensive research, the specific functions and mechanisms of microglia-neuron interactions remain incompletely understood. In this study, we demonstrate that microglia establish direct contact with myelinated axons at Nodes of Ranvier in the spinal cord of mice. The contact associated with neuronal activity occurs in a random scanning pattern. In response to axonal injury, microglia rapidly transform their contact into a robust wrapping form, preventing acute axonal degeneration from extending beyond the nodes. This wrapping behavior is dependent on the function of microglial P2Y12 receptors, which may be activated by ATP released through axonal volume-activated anion channels at the nodes. Additionally, voltage-gated sodium channels (NaV) and two-pore-domain potassium (K2P) channels contribute to the interaction between nodes and glial cells following injury, and inhibition of NaV delays axonal degeneration. Through in vivo imaging, our findings reveal a neuroprotective role of microglia during the acute phase of single spinal cord axon injury, achieved through neuron-glia interaction.

Demand Ischemia due to Gastrointestinal Bleeding Secondary to Ticagrelor

Ticagrelor, an orally consumed antiplatelet medication, acts as an antagonist on the P2Y12 receptor preventing adenosine diphosphate-induced platelet aggregation. Gastrointestinal bleeding triggered by ticagrelor can lead to demand ischemia, as the demand for oxygen by the tissues surpasses the oxygen supply available following acute blood loss. A male patient in his 80s had his antiplatelet medication switched from clopidogrel to ticagrelor following a cardiac stent. He presented to the emergency department a few months later due to black stools and fatigue. The patient had a critically elevated initial troponin level of 780 ng/L which increased to 892 ng/L two hours later. Hemoglobin was low at 8.5 g/dL. The patient suspended usage of ticagrelor and switched back to clopidogrel. Three weeks later, he had an endoscopy, which demonstrated no active bleeding sources.

Chimeras Derived from a P2Y14 Receptor Antagonist and UDP-Sugar Agonists for Potential Treatment of Inflammation.

Tethered glycoconjugates of a naphthalene- and piperidine-containing antagonist of the P2Y14 receptor (PPTN) were synthesized, and their nM receptor binding affinity was determined using a fluorescent tracer in hP2Y14R-expressing whole CHO cells. The rationale for preparing mono- and disaccharide conjugates of the antagonists was to explore the receptor binding site, which we know recognizes a glucose moiety on the native agonist (UDP-glucose), as well as enhance aqueous solubility and pharmacokinetics, including kidney excretion to potentially counteract sterile inflammation. Glycoconjugates with varied linker length, including PEG chains, were compared in hP2Y14R binding, suggesting that an optimal affinity (IC50, nM) in the piperidine series was achieved for triazolyl N-linked glucose conjugates having one (8a, MRS4872, 3.21) or two (7a, MRS4865, 2.40) methylene spacers. In comparison of different carbohydrate conjugates lacking a piperidine moiety but containing triazole spacers, optimal hP2Y14R affinity (IC50, nM) was achieved with N-linked glycosides of fucose 10f (6.19) and lactose 10h (1.88), and C-linked glucose 11a (5.30). Selected compounds were examined in mouse models of conditions known to be ameliorated by P2Y14R antagonists. Two glycoconjugates that lacked a piperidine moiety, N-linked glucose derivative 10a and the isomeric C-linked glucose derivative 11a, were protective in a mouse model of allergic asthma. Piperidine-containing glucose conjugate 7a of intermediate linker length and corresponding glucuronide 7b (MRS4866) protected against neuropathic pain. Thus, glycoconjugation of a known antagonist scaffold has produced less hydrophobic P2Y14R antagonists having substantial in vitro and in vivo activity.

Platelet P2Y12 Receptor Inhibition and Perioperative Patient Management.

P2Y12 receptor inhibitor use increases bleeding risk in surgical patients by inhibiting platelet aggregation. Preoperative monitoring, platelet transfusion, and targeted reversal strategies with novel therapies may help to optimize patient management.

Trifluoro-Icaritin Ameliorates Neuroinflammation Against Complete Freund's Adjuvant-Induced Microglial Activation by Improving CB2 Receptor-Mediated IL-10/β-endorphin Signaling in the Spinal Cord of Rats.

The underlying pathogenesis of chronic inflammatory pain is greatly complex, but the relevant therapies are still unavailable. Development of effective candidates for chronic inflammatory pain is highly urgent. We previously identified that trifluoro-icaritin (ICTF) exhibited a significant therapeutic activity against complete Freund's adjuvant (CFA)-induced chronic inflammatory pain, however, the precise mechanisms remain elusive. Here, the paw withdrawal threshold (PWT), paw withdrawal latency (PWL), and CatWalk gait analysis were used to determine the pain-related behaviors. The expression and co-localization of pain-related signaling molecules were detected by Western blot and immunofluorescence staining. Our results demonstrated that ICTF (3.0mg/kg, i.p.) effectively attenuated mechanical allodynia, thermal hyperalgesia and improved motor dysfunction induced by CFA, and the molecular docking displayed that CB2 receptor may be the therapeutic target of ICTF. Furthermore, ICTF not only up-regulated the levels of CB2 receptor, IL-10, β-endorphin and CD206, but also reduced the expression of P2Y12 receptor, NLRP3, ASC, Caspase-1, IL-1β, CD11b, and iNOS in the spinal cord of CFA rats. Additionally, the immunofluorescence staining from the spinal cord showed that ICTF significantly increased the co-expression between the microglial marker Iba-1 and CB2 receptor, IL-10, β-endorphin, respectively, but markedly decreased the co-localization between Iba-1 and P2Y12 receptor. Conversely, intrathecal administration of CB2 receptor antagonist AM630 dramatically reversed the inhibitory effects of ICTF on CFA-induced chronic inflammatory pain, leading to a promotion of pain hypersensitivity, abnormal gait parameters, microglial activation, and up-regulation of P2Y12 receptor and NLRP3 inflammasome, as well as the inhibition of CB2 receptor and IL-10/β-endorphin cascade. Taken together, these findings highlighted that ICTF alleviated CFA-induced neuroinflammation by enhancing CB2 receptor-mediated IL-10/β-endorphin signaling and suppressing microglial activation in the spinal cord, and uncovered that CB2 receptor may be exploited as a novel and promising target for ICTF treatment of chronic inflammatory pain.