P2Y Receptors Research Articles

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.

Pregabalin inhibits purinergic P2Y2 receptor and TRPV4 to suppress astrocyte activation and to relieve neuropathic pain

BackgroundsTransient receptor potential vanilloid 4 (TRPV4)-mediated astrocyte activation is critical to neuropathic pain. Pregabalin, a widely used drug to treat chronic pain, is reported to lower the intracellular calcium level. However, the molecular mechanism by which pregabalin decreases the intracellular calcium level remains unknown. Purinergic P2Y2 receptor—a member of the G protein-coupled receptor (GPCR) family—regulates calcium-related signal transduction in astrocyte activation. We investigated whether P2Y2 receptor is involved in the pharmacological effects of pregabalin on neuropathic pain. MethodsNeuropathic pain was induced by chronic compression of the dorsal root ganglion (CCD) in rats. Paw withdrawal mechanical threshold (PWMT) was used for behavioral testing. Intracellular calcium concentration was measured using a fluorescent calcium indicator (Fluo-4 AM). ResultsWe found that P2Y2 receptor protein was upregulated and astrocytes were activated in the experimental rats after CCD surgery. Lipopolysaccharide (LPS) increased the intracellular calcium concentration and induced astrocyte activation in cultured astrocytes but was prevented via P2Y2 receptor inhibitor AR-C118925 or pregabalin. Furthermore, plasmid-mediated P2Y2 receptor overexpression induced an elevation of the intracellular calcium levels and inflammation in astrocytes, which was abolished by the TRPV4 inhibitor HC-067047. AR-C118925, HC-067047, and pregabalin relieved neuropathic pain and inflammation in rats after CCD surgery. Finally, plasmid-mediated P2Y2 receptor overexpression induced neuropathic pain in rats, which was abolished by pregabalin administration. ConclusionsPathophysiological variables that upregulated the P2Y2 receptor/TRPV4/calcium axis contribute to astrocyte activation in neuropathic pain. Pregabalin exerts an analgesic effect by inhibiting this pathway.

The role of platelet P2Y12 receptors in inflammation.

Inflammation is a complex pathophysiological process underlying many clinical conditions. Platelets contribute to the thrombo-inflammatory response. Platelet P2Y12 receptors amplify platelet activation, potentiating platelet aggregation, degranulation and shape change. The contents of platelet alpha granules, in particular, act directly on leucocytes, including mediating platelet-leucocyte aggregation and activation via platelet P-selectin. Much evidence for the role of platelet P2Y12 receptors in inflammation comes from studies using antagonists of these receptors, such as the thienopyridines clopidogrel and prasugrel, and the cyclopentyltriazolopyrimidine ticagrelor, in animal and human experimental models. These suggest that antagonism of P2Y12 receptors decreases markers of inflammation with some evidence that this reduces incidence of adverse clinical sequelae during inflammatory conditions. Interpretation is complicated by pleiotropic effects such as those of the thienopyridines on circulating leucocyte numbers and of ticagrelor on adenosine reuptake. The available evidence suggests that P2Y12 receptors are prominent mediators of inflammation and P2Y12 receptor antagonism as a potentially powerful strategy in a broad range of inflammatory conditions. LINKED ARTICLES: This article is part of a themed issue on Platelet purinergic receptor and non-thrombotic disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.4/issuetoc.

P-113 - Design and synthesis of fluorinated pyrazolidine-3,5-dione derivatives as potential P2Y12 receptor PET tracers

P-113 - Design and synthesis of fluorinated pyrazolidine-3,5-dione derivatives as potential P2Y12 receptor PET tracers

Use of Antiplatelet Drugs Targeting Platelet P2Y12 Receptor Is Associated with Reduced Risk for Infectious Death in Veterans with CKD

Use of Antiplatelet Drugs Targeting Platelet P2Y12 Receptor Is Associated with Reduced Risk for Infectious Death in Veterans with CKD

Systematic P2Y receptor survey identifies P2Y11 as modulator of immune responses and virus replication in macrophages.

The immune system is in place to assist in ensuring tissue homeostasis, which can be easily perturbed by invading pathogens or nonpathogenic stressors causing tissue damage. Extracellular nucleotides are well known to contribute to innate immune signaling specificity and strength, but how their signaling is relayed downstream of cell surface receptors and how this translates into antiviral immunity is only partially understood. Here, we systematically investigated the responses of human macrophages to extracellular nucleotides, focusing on the nucleotide-sensing GPRC receptors of the P2Y family. Time-resolved transcriptomic analysis showed that adenine- and uridine-based nucleotides induce a specific, immediate, and transient cytokine response through the MAPK signaling pathway that regulates transcriptional activation by AP-1. Using receptor trans-complementation, we identified a subset of P2Ys (P2Y1, P2Y2, P2Y6, and P2Y11) that govern inflammatory responses via cytokine induction, while others (P2Y4, P2Y11, P2Y12, P2Y13, and P2Y14) directly induce antiviral responses. Notably, P2Y11 combined both activities, and depletion or inhibition of this receptor in macrophages impaired both inflammatory and antiviral responses. Collectively, these results highlight the underappreciated functions of P2Y receptors in innate immune processes.

Purinergic P2Y2 receptor-induced activation of endothelial TRPV4 channels mediates lung ischemia-reperfusion injury.

Lung ischemia-reperfusion injury (IRI), characterized by inflammation, vascular permeability, and lung edema, is the major cause of primary graft dysfunction after lung transplantation. Here, we investigated the cellular mechanisms underlying lung IR-induced activation of endothelial TRPV4 channels, which play a central role in lung edema and dysfunction after IR. In a left lung hilar-ligation model of IRI in mice, we found that lung IRI increased the efflux of ATP through pannexin 1 (Panx1) channels at the endothelial cell (EC) membrane. Elevated extracellular ATP activated Ca2+ influx through endothelial TRPV4 channels downstream of purinergic P2Y2 receptor (P2Y2R) signaling. P2Y2R-dependent activation of TRPV4 channels was also observed in human and mouse pulmonary microvascular endothelium in ex vivo and in vitro models of IR. Endothelium-specific deletion of P2Y2R, TRPV4, or Panx1 in mice substantially prevented lung IRI-induced activation of endothelial TRPV4 channels and lung edema, inflammation, and dysfunction. These results identify endothelial P2Y2R as a mediator of the pathological sequelae of IRI in the lung and show that disruption of the endothelial Panx1-P2Y2R-TRPV4 signaling pathway could be a promising therapeutic strategy for preventing lung IRI after transplantation.

Presynaptic Purinergic Modulation of the Rat Neuro-Muscular Transmission.

ATP, being a well-known universal high-energy compound, plays an important role as a signaling molecule and together with its metabolite adenosine they both attenuate the release of acetylcholine in the neuro-muscular synapse acting through membrane P2 and P1 receptors, respectively. In this work, using a mechanomyographic method, we analyzed the presynaptic mechanisms by which ATP and adenosine can modulate the transduction in the rat m. soleus and m. extensor digitorum longus. N-ethylmaleimide, a G-protein antagonist, prevents the modulating effects of both ATP and adenosine. The action of ATP is abolished by chelerythrin, a specific phospholipase C inhibitor, while the inhibitory effect of adenosine is slightly increased by Rp-cAMPS, an inhibitor of protein kinase A, and by nitrendipine, a blocker of L-type Ca2+ channels. The addition of DPCPX, an A1 receptor antagonist, fully prevents the inhibitory action of adenosine in both muscles. Our data indicate that the inhibitory action of ATP involves metabotropic P2Y receptors and is mediated by phospholipase C dependent processes in rat motor neuron terminals. We suggest that the presynaptic effect of adenosine consists of negative and positive actions. The negative action occurs by stimulation of adenosine A1 receptors while the positive action is associated with the stimulation of adenosine A2A receptors, activation of protein kinase A and opening of L-type calcium channels. The combined mechanism of the modulating action of ATP and adenosine provides fine tuning of the synapse to fast changing conditions in the skeletal muscles.

Pharmacological interaction and immune response of purinergic receptors in therapeutic modulation.

Nucleosides and purine nucleotides serve as transmitter and modulator agents that extend their functions beyond the cell. In this context, purinergic signaling plays a crucial role in regulating energy homeostasis and modulating metabolic alterations in tumor cells. Therefore, it is essential to consider the pharmacological targeting of purinergic receptors (PUR), which encompass the expression and inhibition of P1 receptors (metabotropic adenosine receptors) as well as P2 receptors (extracellular ATP/ADP) comprising P2X and P2Y receptors. Thus, the pharmacological interaction between inhibitors (such as RNA, monoclonal antibodies, and small molecules) and PUR represents a key aspect in facilitating the development of therapeutic interventions. Moreover, this review explores recent advancements in pharmacological inhibitors and the regulation of innate and adaptive immunity of PUR, specifically in relation to immunological and inflammatory responses. These responses encompass the release of pro-inflammatory cytokines (PIC), the production of reactive oxygen and nitrogen species (ROS and RNS), the regulation of T cells, and the activation of inflammasomes in all human leukocytes.

Pyrimidinergic receptor P2Y6 expression is elevated in lung adenocarcinoma and is associated with poor prognosis.

Previous in vitro studies have indicated that pyrimidinergic receptor P2Y6 (P2RY6, P2Y6 receptor) may function as a cancer-promoting factor in lung adenocarcinoma (LUAD). However, the prognostic significance of P2RY6 expression in LUAD has not been investigated. This study aimed to assess the impact of P2RY6 expression on the survival of patients with LUAD. First, we assessed P2RY6 mRNA and protein expression in LUAD and non-cancerous lung tissues using the online bioinformatics analysis tool GEPIA, fresh LUAD tissues, and LUAD tissue microarrays (TMAs). Second, we investigated the correlation between P2RY6 expression and clinicopathological parameters of LUAD patients based on data from The Cancer Genome Atlas (TCGA) database and TMAs. Finally, we analyzed the prognostic significance of P2RY6 expression in LUAD using the online survival analysis tool Kaplan-Meier Plotter and data from TMAs. We demonstrated that P2RY6 mRNA and protein expression levels in LUAD tissues were significantly higher than those in non-cancerous lung tissues. The expression of P2RY6 in LUAD was positively correlated with poor differentiation, more lymph node metastasis, and more advanced clinical stage. Higher P2RY6 expression level was correlated with shorter survival of the LUAD patients. Univariate and multivariate Cox regression analyses indicated that higher P2RY6 tumor expression was an independent unfavorable prognostic factor for LUAD patients. P2RY6 expression was elevated in LUAD and correlated with poor prognosis.

Extracellular ATP Neurotransmission and Nicotine Sex-Specifically Modulate Habenular Neuronal Activity in Adolescence.

The recent increase in the use of nicotine products by teenagers has revealed an urgent need to better understand the impact of nicotine on the adolescent brain. Here, we sought to examine the actions of extracellular ATP as a neurotransmitter and to investigate whether ATP and nicotinic signaling interact during adolescence. With the GRABATP (G-protein-coupled receptor activation-based ATP sensor), we first demonstrated that nicotine induces extracellular ATP release in the medial habenula, a brain region involved in nicotine aversion and withdrawal. Using patch-clamp electrophysiology, we then demonstrated that activation of the ATP receptors P2X or P2Y1 increases the neuronal firing of cholinergic neurons. Surprisingly, contrasting interactive effects were observed with nicotine exposure. For the P2X receptor, activation had no observable effect on acute nicotine-mediated activity, but during abstinence after 10 d of nicotine exposure, coexposure to nicotine and the P2X agonist potentiated neuronal activity in female, but not male, neurons. For P2Y1 signaling, a potentiated effect of the agonist and nicotine was observed with acute exposure, but not following extended nicotine exposure. These data reveal a complex interactive effect between nicotinic and ATP signaling in the adolescent brain and provide mechanistic insights into extracellular ATP signaling with sex-specific alterations of neuronal responses based on prior drug exposure.SIGNIFICANCE STATEMENT In these studies, it was discovered that nicotine induces extracellular ATP release in the medial habenula and subsequent activation of the ATP purinergic receptors increases habenular cholinergic neuronal firing in the adolescent brain. Interestingly, following extended nicotine exposure, nicotine was found to alter the interplay between purinergic and nicotinic signaling in a sex-specific manner. Together, these studies provide a novel understanding for the role of extracellular ATP in mediating habenular activity and reveal how nicotine exposure during adolescence alters these signaling mechanisms, which has important implications given the high incidence of e-cigarette/vape use by youth.

Human peripheral blood mononuclear cells display a temporal evolving inflammatory profile after myocardial infarction and modify myocardial fibroblasts phenotype

Pathophysiological response after acute myocardial infarction (AMI) is described as a three-stage model involving temporal phenotypic modifications of both immune cells and fibroblasts: a primary inflammatory phase, followed by a reparative phase and a fibrous scar maturation phase. Purinergic receptors, particularly the P2Y11 receptor, have been reported to be involved in the regulation of inflammation after ischemia and could act for the resolution of inflammation after AMI. For the first time, we characterized the immuno-inflammatory and P2Y11 expression profiles of peripheral blood mononuclear cells (PBMC) from AMI patients and analyzed the consequences of presenting these cells to cardiac fibroblasts in vitro. PBMC from 178 patients were collected at various times after reperfused ST-segment elevation AMI, from H0 to M12. Expression level of P2RY11 and genes involved in tolerogenic profile of dendritic cells and T cell polarization were evaluated by RT-PCR. P2Y11 protein expression was assessed by flow cytometry. PBMC and human cardiac fibroblasts (HCF) were cocultured and α-SMA/vimentin ratio was analyzed by flow cytometry. Within the first 48 h after AMI, expression levels of HMOX1, STAT3 and CD4 increased while IDO1 and TBX21/GATA3 ratio decreased. Concomitantly, the expression of P2RY11 increased in both T and B cells. In vitro, PBMC collected at H48 after AMI induced an increase in α-SMA/vimentin ratio in HCF. Our results suggest that human PBMC display an evolving inflammatory profile with reparative characteristics the first two days after AMI and secrete soluble mediators leading to the fibroblastic proteins modification, thus participating to myocardial fibrosis.

Besnoitia besnoiti-induced neutrophil clustering and neutrophil extracellular trap formation depend on P2X1 purinergic receptor signaling.

Bovine besnoitiosis is a re-emerging cattle disease caused by the cyst-forming apicomplexan parasite Besnoitia besnoiti. Neutrophil extracellular trap (NET) formation represents an efficient innate immune mechanism of polymorphonuclear neutrophils (PMN) against apicomplexan parasites, including B. besnoiti. PMN purinergic signaling was proposed as a critical factor for NET formation. One important purinergic ligand is ATP, which is recognized as a danger signal and released into the extracellular space acting as an autocrine/paracrine signaling molecule. ATP-driven effects on PMN via the nucleotide P2 receptor family include chemotaxis, reactive oxygen species (ROS) production, and NET formation. So far, data on both PMN ATP concentrations and the role of ATP as a key modulator of purinergic signaling in B. besnoiti tachyzoite-triggered bovine NETosis is scarce. Current data showed that B. besnoiti tachyzoite exposure to bovine PMN neither changed total PMN ATP nor extracellular ATP quantities even though it significantly triggered NET formation. Moreover, B. besnoiti tachyzoite-exposed PMN revealed enhanced oxygen consumption rates (OCR) as quantified by the Seahorse metabolic analyzer. Exogenous supplementation of ATP or non-hydrolizable ATP (ATPγS) led to increased extracellular acidification rates (ECAR) but failed to alter tachyzoite-induced oxidative responses (OCR) in exposed PMN. In addition, exogenous supplementation of ATPγS, but not of ATP, boosted B. besnoiti tachyzoite-induced anchored NET formation. Referring to purinergic signaling, B. besnoiti tachyzoite-triggered anchored NET formation revealed P2X1 purinergic as receptor-dependent since it was blocked by the P2X1 inhibitor NF449 at an IC50 of 1.27 µM. In contrast, antagonists of P2Y2, P2Y6, P2X4, and P2X7 purinergic receptors all failed to affect parasite-driven NETosis. As an interesting finding, we additionally observed that B. besnoiti tachyzoite exposure induced PMN clustering in a P2X1-dependent manner. Thus, we identified P2X1 purinergic receptor as a pivotal molecule for both B. besnoiti tachyzoite-induced PMN clustering and anchored NET formation.

PB0803 P2Y12 Receptor Expression on Monocytes, Monocyte-Derived Macrophages and Dendritic Cells and Modulation by Ticagrelor

PB0803 P2Y12 Receptor Expression on Monocytes, Monocyte-Derived Macrophages and Dendritic Cells and Modulation by Ticagrelor

P2Y6 Receptor-Dependent Microglial Phagocytosis of Synapses during Development Regulates Synapse Density and Memory.

During brain development, excess synapses are pruned (i.e., removed), in part by microglial phagocytosis, and dysregulated synaptic pruning can lead to behavioral deficits. The P2Y6 receptor (P2Y6R) is known to regulate microglial phagocytosis of neurons, and to regulate microglial phagocytosis of synapses in cell culture and in vivo during aging. However, currently it is unknown whether P2Y6R regulates synaptic pruning during development. Here, we show that P2Y6R KO mice of both sexes had strongly reduced microglial internalization of synaptic material, measured as Vglut1 within CD68-staining lysosomes of microglia at postnatal day 30 (P30), suggesting reduced microglial phagocytosis of synapses. Consistent with this, we found an increased density of synapses in the somatosensory cortex and the CA3 region and dentate gyrus of the hippocampus at P30. We also show that adult P2Y6R KO mice have impaired short- and long-term spatial memory and impaired short- and long-term recognition memory compared with WT mice, as measured by novel location recognition, novel object recognition, and Y-maze memory tests. Overall, this indicates that P2Y6R regulates microglial phagocytosis of synapses during development, and this contributes to memory capacity.SIGNIFICANCE STATEMENT The P2Y6 receptor (P2Y6R) is activated by uridine diphosphate released by neurons, inducing microglial phagocytosis of such neurons or synapses. We tested whether P2Y6R regulates developmental synaptic pruning in mice and found that P2Y6R KO mice have reduced synaptic material within microglial lysosomes, and increased synaptic density in the brains of postnatal day 30 mice, consistent with reduced synaptic pruning during development. We also found that adult P2Y6R KO mice had reduced memory, consistent with persistent deficits in brain function, resulting from impaired synaptic pruning. Overall, the results suggest that P2Y6R mediates microglial phagocytosis of synapses during development, and the absence of this results in memory deficits in the adult.

A-149 Performance Characteristics of VerifyNow PRU and ARU Tests During a Clinical Method Verification Exercise

Abstract Background Dual antiplatelet therapy with aspirin and a platelet P2Y12 receptor antagonist is indicated for the prevention of atherothrombotic events in patients with acute coronary syndromes and for those undergoing percutaneous coronary intervention procedure. Two different assays are available in the VerifyNow Test device for monitoring the anti-platelet therapy response. The aspirin assay (ARU Test) utilizes arachidonic acid as an agonist and is sensitive to acyl salicylic acid. The P2Y12 assay (PRU test) is sensitive to thienopyridines (such as clopidogrel, prasugrel, ticagrelor) and uses adenosine diphosphate (ADP) as an agonist. The PRU test is a non-waived test and ARU test is a waived test. A comprehensive method performance verification is required for the PRU test. We evaluated performance characteristics of the VerifyNow PRU Test and ARU Test for clinical use. Methods The standard precision and accuracy study using two levels (low and high) of quality control materials were performed (N = 10) for both the assays. Alternative qualitative method comparison was carried out (N = 49) using the VerifyNow PRU Test in a reference lab and in-house. The in-house inter-instrument comparisons were carried out (N = 42). The blood samples were obtained from patients taking P2Y12 inhibitors and from normal donors not on any drugs. The results of the PRU Test are expressed in P2YI2 reaction units (PRU). The VerifyNow-Aspirin assay results are expressed as aspirin reaction units (ARU). The statistical analysis to evaluate performance characteristics was carried out using the EP Evaluator. Results The VerifyNow device 1561 precision characteristics for low QC (Obs Mean = 1.5 PRU (N = 10), SD = 0.2; 95% CI for Obs Mean 1.0 to 2.0 PRU) and high QC (Obs Mean = 258.3 PRU (N = 10), SD = 8.2; 95% CI for Obs Mean 252.4 to 264.2 PRU) were within acceptable performance limits. The CV for high QC was 3.2%. The ARU test also demonstrated high precision for two levels (Low QC Obs Mean = 350ARU (N = 10), SD = 0.0); High QC Obs Mean = 583.3 (N = 10), SD = 7.2; 95% CI for Obs Mean = 578.1–588.5) with a CV of 1.2%. The PRU Test Method PRU 1561 In House vs Ref Method Verify Now PRU Test (N = 49) demonstrated overall agreement of 93.9% with positive agreement (intended use population on drugs, N = 27) of 92% and negative agreement (normal non-drug group, N = 22) of 95.8% (Cohen’s Kappa = 87.8%; Kappa >75% indicates “"high” agreement). The McNemar Test for Symmetry passed (P > 0.999, Fisher’s Exact test) in this qualitative method comparison. A value of P < 0.05 would suggest the methods are significantly different. The other in-house instrument 1562 also demonstrated comparable or better performance characteristics. Conclusion It is important to confirm the medical decision limit for the intended use population and determine acceptance criteria while considering biologic variability. However, the reference range verifications with drug responders and non-responders are not always feasible and cost-effective. Based on the qualitative method comparison in this study, we have transferred the medical decision limits from the peer group. The in-house multi-instrument comparison should be repeated every six months to monitor the performance of the instruments.

Phytochemical fingerprinting and evaluation of in silico anti-thrombotic properties of Justicia adhatoda L. and Cordia dichotoma Frost.

The study aimed to characterize hydro-methanolic (25%) extracts of Justicia adhatoda L. (stem and flower) and Cordia dichotoma Frost. (Stem and fruit) and evaluate the in silico thrombolytic properties of the major phytocompounds present in the plants. In the preliminary fluorescence imaging through treatment by different reagents, both plants were found to be pharmacologically active. Further qualitative screening of phytochemicals, spectroscopy-based techniques, namely, UV-Vis Spectroscopy and FTIR, revealed various classes of compounds such as polyacetylenes, aglycones, quercetin, anthocyanins, anthraquinones, alkaloids, chalcones and aurones, flavanols, carotenoids, and flavanones. Further, by the application of Thin Layer Chromatography, phenols and flavonoids, namely Catechol, Kaempferol, Quercetin, and Lutein, along with other compounds like Chlorophyll b, Glutamic Acid, and Tryptophan were identified from the extracts. Finally, in the molecular docking study, three compounds, Datiscoside and Robinin of C. dichotoma and Daucosterol of J. adhatoda showed high binding energies (-10.224, -9.547 and -9.262 kcal mol-1 respectively) towards the G-protein coupled thrombotic platelet aggregation receptor P2Y1 when compared to that of the control MRS2500 (-7.148 kcal mol-1).

Pannexin-1 opening in neuronal edema causes cell death but also leads to protection via increased microglia contacts

Neuronal swelling during cytotoxic edema is triggered by Na+ and Cl- entry and is Ca2+ independent. However, the causes of neuronal death during swelling are unknown. Here, we investigate the role of large-conductance Pannexin-1 (Panx1) channels in neuronal death during cytotoxic edema. Panx1 channel inhibitors reduce and delay neuronal death in swelling triggered by voltage-gated Na+ entry with veratridine. Neuronal swelling causes downstream production of reactive oxygen species (ROS) that opens Panx1 channels. We confirm that ROS activates Panx1 currents with whole-cell electrophysiology and find scavenging ROS is neuroprotective. Panx1 opening and subsequent ATP release attract microglial processes to contact swelling neurons. Depleting microglia using the CSF1 receptor antagonist PLX3397 or blocking P2Y12 receptors exacerbates neuronal death, suggesting that the Panx1-ATP-dependent microglia contacts are neuroprotective. We conclude that cytotoxic edema triggers oxidative stress in neurons that opens Panx1 to trigger death but also initiates neuroprotective feedback mediated by microglia contacts.

Institutional Variability in Red Blood Cell Transfusion With Coronary Bypass in a Statewide Database

BackgroundThe decision to perform transfusion is common but varies among centers and surgeons. This study looked at variables associated with red blood cell (RBC) transfusion in a statewide database. The study aimed to understand discrepancies in transfusion rates among hospitals and to establish whether the hospital itself was a significant variable in transfusion, independent of variables known to affect transfusion in patients undergoing cardiac surgical procedures. MethodsThe Maryland Cardiac Surgery Quality Initiative is a consortium of centers in the state. Patients undergoing isolated coronary artery bypass grafting from January 2018 to June 2020 from 10 centers in Maryland were included. Multivariable logistic regression was used to determine probability of RBC transfusion with covariates, including age, preoperative hemoglobin value, The Society of Thoracic Surgeons predicted risk of mortality, emergency status, preoperative adenosine diphosphate receptor blocker use, sex, body mass index, and off-pump status. ResultsA total of 5343 patients were included and had an overall RBC transfusion rate of 30.3% (range, 11.3%-55.8%). There was significant variability in the incidence of RBC transfusion among hospitals (χ2 = 604.7; P < .001). After covariate adjustment, a significant effect of hospital on transfusion remained (Wald = 547.3; P < .001). Hospital variation in RBC transfusion was not correlated with hospital variation in median age (P = .467), hemoglobin (P 0 855), The Society of Thoracic Surgeons predicted risk of mortality (P = .855), or sex (P = .726). ConclusionsIn a statewide analysis, wide variability in transfusion rates was observed, with hospital-specific management strongly associated with RBC transfusion. This study suggests that RBC transfusion may be affected by the culture and practices of an institution independent of clinical and demographic variables.

Optimising antithrombotic therapy after acute coronary syndromes and percutaneous coronary interventions

Dual antiplatelet therapy, combining aspirin with a platelet P2Y12 receptor inhibitor, is the standard treatment for acute coronary syndrome patients undergoing percutaneous coronary intervention. The optimal type and duration of dual antiplatelet therapy depend on the patient's risk for ischemic and hemorrhagic complications. De-escalation strategies, such as switching to a less potent P2Y12 inhibitor, reducing the dose, or discontinuing one of the antiplatelet agents, may be suitable for high-risk bleeding patients with low risk of recurrent ischemic events, and platelet function testing and genetic testing can guide de-escalation. For patients at high ischemic risk, strategies include drug switching, dose escalation, or adding a new drug. Patients at high ischemic and hemorrhagic risk require individualized treatment decisions and trade-off considerations.