New role for cardiomyocyte Bmal1 in the regulation of sex-specific heart transcriptomes.

It has been well established that cardiovascular diseases exhibit significant differences between sexes in both preclinical models and humans. In addition, there is growing recognition that disrupted circadian rhythms can contribute to the onset and progression of cardiovascular diseases. However little is known about sex differences between the cardiac circadian clock and circadian transcriptomes in mice. Here, we show that the the core clock genes are expressed in common in both sexes but the circadian transcriptome of the mouse heart is very sex-specific. Hearts from female mice expressed significantly more rhythmically expressed genes (REGs) than male hearts and the temporal pattern of REGs was distinctly different between sexes. We next used a cardiomyocyte-specific knock out of the core clock gene, Bmal1, to investigate its role in sex-specific gene expression in the heart. All sex differences in the circadian transcriptomes were significantly diminished with cardiomyocyte-specific loss of Bmal1. Surprisingly, loss of cardiomyocyte Bmal1 also resulted in a roughly 8-fold reduction in the number of all the differentially expressed genes between male and female hearts. We conclude that cardiomyocyte-specific Bmal1, and potentially the core clock mechanism, is vital in conferring sex-specific gene expression in the adult mouse heart.

Platelet FcγRIIa expression in patients with stable coronary artery disease.

OBJECTIVES: FcÉ£RIIa amplifies platelet activation and greater expression increases platelet reactivity. In patients with myocardial infarction (MI), high platelet FcÉ£RIIa identifies patients with an approximately 4-fold greater risk of MI, stroke, and death. We compared platelet FcÉ£RIIa in 2 groups: (1) patients who had not had an MI in the previous year and were undergoing cardiac catheterization and percutaneous coronary intervention (PCI) labeled as stable coronary artery disease (CAD), and (2) previously obtained results in patients with MI (n = 197). METHODS: Patients undergoing cardiac catheterization and PCI were enrolled. FcÉ£RIIa expression was quantified with the use of flow cytometry. Comparisons were made with Mann-Whitney Rank Sum Test and Chi Squared analysis. Significance was defined as P less than .05. RESULTS: Compared to patients with MI, patients with stable CAD (n = 49) were older (70 ± 9 years vs 63 ± 12 years) and were more likely to have had prior MI (43% vs 23%), prior revascularization (62% vs 33%), diabetes (35% vs 24%), and hypertension (98% vs 66%). In patients with stable CAD, platelet FcÉ£RIIa was, on average, lower than that seen in patients with acute MI (9746 ± 4316 vs 11 479 ± 2405 molecules/platelet, P less than .001). Patients with stable CAD exhibited a range of platelet FcÉ£RIIa (~4500 to ~27 000 molecules/platelet) similar to that seen in acute MI patients (~6500 to ~30 000 molecules/platelet). CONCLUSIONS: Compared to patients with MI, patients with stable CAD had, on average, lower platelet FcÉ£RIIa. However, the range of platelet FcÉ£RIIa was similar to that seen in patients with MI. These results support future studies designed to assess the prognostic implications of platelet FcÉ£RIIa in patients with stable CAD.

Exploring the potential cost-effectiveness of a novel platelet assay for guiding dual antiplatelet therapy duration in acute coronary syndrome patients following percutaneous coronary intervention.

OBJECTIVE: Duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) influences ischemic and bleeding events. Platelet expression of constant fragment of immunoglobulin, low affinity IIa, receptor (FcγRIIa) independently predicts risk of ischemic complications and is proposed as a tool to guide individualized care. METHODS: We used a Markov model to predict lifetime ischemic and bleeding events and healthcare costs in acute myocardial infarction (MI) patients treated with PCI and DAPT and to project cost-effectiveness of platelet FcγRIIa-assay-guided care (30:3 months DAPT for patients at high: low ischemic risk) versus current standard care (12 months DAPT) from the perspective of the US healthcare system. Model inputs included assay sensitivity and specificity, ischemic and bleeding event rates, and impacts on quality of life, mortality, and costs. Assay cost was $90. Sensitivity analyses were conducted over a range of plausible clinical and cost assumptions. RESULTS: Under base case assumptions, platelet FcγRIIa-assay-guided DAPT duration was projected to increase lifetime costs by $19 versus standard care, with an associated incremental cost-effectiveness ratio (ICER) of $436 per quality-adjusted life-year (QALY) gained. Assay-guided DAPT duration was consistent with high-value care (ICER < $50 000/QALY gained) over a broad range of alternative assumptions. CONCLUSION: Based on a decision-analytic model, for patients with MI treated with PCI, the additional costs of the platelet FcγRIIa assay for guiding DAPT duration would be largely offset by reductions in downstream event-related costs, and assay-guided care would be highly cost-effective by current standards. These findings require confirmation in prospective studies and in a randomized clinical trial of assay-guided versus nonassay-guided DAPT duration.

Pharmacokinetic and pharmacodynamic profiles of a novel phospholipid-aspirin complex liquid formulation and low dose enteric-coated aspirin: results from a prospective, randomized, crossover study.

Low dose enteric-coated aspirin (EC-ASA) is routinely used for secondary cardiovascular event prevention. However, absorption of EC tablets is poor, which can result in subtherapeutic antiplatelet effects. Phospholipid-aspirin liquid filled capsules (PL-ASA) are a novel FDA-approved immediate-release formulation designed to reduce gastrointestinal (GI) injury by limiting direct contact with the stomach lining. We compared the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of PL-ASA versus EC-ASA at a low dose. This randomized, open-label, crossover study assessed PK and PD following a single 81-mg dose of PL-ASA versus EC-ASA under fasting conditions in 36 volunteers without cardiovascular disease between 18 and 75 years of age. Volunteers were randomly assigned 1:1 to either PL-ASA then EC-ASA or vice versa with a minimum 14-day washout. Assessments included PK parameters for acetylsalicylic acid and salicylic acid, platelet aggregation in response to arachidonic acid (AA), and serum thromboxane B2 (TxB2) assessments over 24 h. PL-ASA was rapidly absorbed. PL-ASA reached Tmax 3 h earlier (1.01 vs. 4.00 h, p < 0.0001), with almost double the Cmax (720 vs. 368 ng/mL, p < 0.0001) and overall 44% higher exposure of acetylsalicylic acid (AUC0-t: 601 vs. 416 h*ng/mL, p = 0.0013) compared with EC-ASA. Within 1 h of dosing, PL-ASA achieved significantly lower residual platelet aggregation, which persisted for the full 24 h (median AA-LTA was 47% with PL-ASA vs. 80.5% with EC-ASA; p = 0.0022 at hour-24). Treatment with PL-ASA also resulted in significantly lower serum TxB2 concentrations at each time point compared with EC-ASA (all p-values < 0.05). PL-ASA resulted in faster and more complete aspirin absorption paralleled by more prompt and potent platelet inhibition compared with EC-ASA after a single 81 mg dose. PL-ASA represents an attractive novel aspirin formulation for the secondary prevention of cardiovascular events.Clinical Trial Registration ClinicalTrials.gov identifier: NCT04811625.

The flax genome reveals orbitide diversity.

BACKGROUND: Ribosomally-synthesized cyclic peptides are widely found in plants and exhibit useful bioactivities for humans. The identification of cyclic peptide sequences and their precursor proteins is facilitated by the growing number of sequenced genomes. While previous research largely focused on the chemical diversity of these peptides across various species, there is little attention to a broader range of potential peptides that are not chemically identified. RESULTS: A pioneering study was initiated to explore the genetic diversity of linusorbs, a group of cyclic peptides uniquely occurring in cultivated flax (Linum usitatissimum). Phylogenetic analysis clustered the 5 known linusorb precursor proteins into two clades and one singleton. Preliminary tBLASTn search of the published flax genome using the whole protein sequence as query could only retrieve its homologues within the same clade. This limitation was overcome using a profile-based mining strategy. After genome reannotation, a hidden Markov Model (HMM)-based approach identified 58 repeats homologous to the linusorb-embedded repeats in 8 novel proteins, implying that they share common ancestry with the linusorb-embedded repeats. Subsequently, we developed a customized profile composed of a random linusorb-like domain (LLD) flanked by 5 conserved sites and used it for string search of the proteome, which extracted 281 LLD-containing repeats (LLDRs) in 25 proteins. Comparative analysis of different repeat categories suggested that the 5 conserved flanking sites among the non-homologous repeats have undergone convergent evolution driven by functional selection. CONCLUSIONS: The profile-based mining approach is suitable for analyzing repetitive sequences. The 25 LLDR proteins identified herein represent the potential diversity of cyclic peptides within the flax genome and lay a foundation for further studies on the functions and evolution of these protein tandem repeats.

Antithrombotic drug removal from whole blood using Haemoadsorption with a porous polymer bead sorbent.

AIM: To evaluate the ability of the DrugSorb™-AntiThrombotic Removal (ATR) haemoadsorption device utilizing porous polymer bead sorbent technology to remove three commonly used antithrombotic drugs from whole blood. METHODS AND RESULTS: We evaluated the removal of apixaban, rivaroxaban, and ticagrelor by the DrugSorb-ATR haemoadsorption device in a benchtop clinical scale model using bovine whole blood. Blood spiked at clinically relevant concentrations of an antithrombotic agent was continuously circulated through a 300-mL DrugSorb-ATR haemoadsorption device at a flow rate of 300 mL/min. Drug concentration was monitored over 6 h to evaluate drug removal. Results were compared with a control circuit without the haemoadsorption device. Removal rates at 30, 60, 120, and 360 minutes were: apixaban: 81.5%, 96.3%, 99.3% >99.8%; rivaroxaban: 80.7%, 95.1%, 98.9%, >99.5%; ticagrelor: 62.5%; 75%, 86.6%, >95% (all P <0.0001 vs. control). Blood pH and haematological parameters were not significantly affected by the DrugSorb-ATR haemoadsorption device when compared with the control circuit. CONCLUSION: DrugSorb-ATR efficiently removes apixaban, rivaroxaban, and ticagrelor in a clinical-scale benchtop recirculation circuit with the bulk of removal occurring in the first 60 minutes. The clinical implications of these findings are currently investigated in patients undergoing on-pump cardiothoracic surgery in two US pivotal trials (ClinicalTrials.gov Identifiers: NCT04976530 and NCT05093504).

Intracranial atherosclerosis: Review of imaging features and advances in diagnostics.

Intracranial atherosclerotic disease is one of the leading causes of ischemic strokes and poses a moderate risk of recurrence. Diagnosis is currently limited to stenosis on luminal imaging, which likely underestimates the true prevalence of the disease. Detection of non-stenosing intracranial atherosclerosis is important in order to optimize secondary stroke prevention strategies. This review collates findings from the early seminal trials and the latest studies in advanced radiological techniques that characterize symptomatic intracranial atherosclerotic disease across various imaging modalities. While computed tomography angiography (CTA) and magnetic resonance angiography (MRA) comprise diagnostic mainstays in identifying stenotic changes secondary to atherosclerosis, emerging techniques such as high-resolution MRA, quantitative MRA, and computational fluid dynamics may reveal a myriad of other underlying pathophysiological mechanisms.

Pharmacokinetic and Pharmacodynamic Profile of a Novel Phospholipid Aspirin Formulation.

Aspirin is one of the most widely used medicines. Although aspirin is commonly utilized for the treatment of several medical conditions, its broadest uptake is for the prevention of recurrent ischemic events in patients with atherosclerotic disease. Its mechanism of action of inhibiting platelet activation via blockade of thromboxane A2 production is unique and is not covered by any other antiplatelet agents. While plain, uncoated, immediate-release aspirin is used in acute settings to help assure rapid absorption, enteric-coated aspirin formulations dominate current chronic use, particularly in North America, including for secondary prevention of cardiovascular events. The unmet needs with current aspirin formulations include a high risk of gastrointestinal (GI) adverse events with plain aspirin, which enteric-coated formulations are not able to overcome, and subject to erratic absorption leading to reduced drug bioavailability. These observations underscore the need for aspirin formulations with a more favorable safety and efficacy profile. Phospholipid-aspirin complex (PL-ASA) is a novel formulation designed to address these needs. It is associated with reduced local acute GI injury compared with plain aspirin, and predictable absorption resulting in more reliable platelet inhibition compared with enteric-coated tablets. This review explores the rationale and pharmacologic profile of PL-ASA intended to address the unmet needs for aspirin therapy.

Rationale and design of the safe and timely antithrombotic removal - ticagrelor (STAR-T) trial: A prospective, multi-center, double-blind, randomized controlled trial evaluating reductions in postoperative bleeding with intraoperative removal of ticagrelor by the drugsorb™-ATR device in patients undergoing cardiothoracic surgery within 48 hours from last ticagrelor dose.

BACKGROUND: Ticagrelor is often administered to patients with acute coronary syndromes. However, when these patients require urgent or emergent cardiothoracic (CT) surgery the presence of ticagrelor significantly increases surgical bleeding. The goal of the current trial is to evaluate the effectiveness and safety of the DrugSorb-ATR hemoadsorption device for the intraoperative removal of ticagrelor to reduce postoperative bleeding in the above patient population. The Safe and Timely Antithrombotic Removal - Ticagrelor (STAR-T) Trial is a multi-center, double-blind, randomized, controlled trial enrolling patients who require cardiothoracic surgery on cardiopulmonary bypass (CPB) within 48 hours of last ticagrelor dose. METHODS: Subjects will be randomized 1:1 to receive either the DrugSorb-ATR device or an identical sham device during CPB. The study will enroll up to 120 subjects at 20 U.S centers, and the primary outcome is the composite of fatal perioperative bleeding, moderate/severe/massive bleeding according to the Universal Definition of Perioperative Bleeding in Cardiac Surgery (UDPB), and 24 hours chest tube drainage. The components of the composite are hierarchically ranked according to clinical significance and the primary analysis will utilize the Win Ratio method. Percent change in ticagrelor levels before and after CPB (drug removal) will be the key secondary endpoint. An independent Clinical Events Committee will adjudicate all clinical endpoints including safety endpoints relating to postoperative thrombotic events. Subjects will be followed through 30 days after the index operation. CONCLUSIONS: The results from STAR-T, if positive, will potentially support FDA market approval for DrugSorb-ATR, and provide a solution to an important unmet clinical need.

Endothelial Shear Stress and Platelet FcγRIIa Expression in Intracranial Atherosclerotic Disease.

Intracranial atherosclerotic disease (ICAD) has been characterized by the degree of arterial stenosis and downstream hypoperfusion, yet microscopic derangements of endothelial shear stress at the luminal wall may be key determinants of plaque growth, vascular remodeling and thrombosis that culminate in recurrent stroke. Platelet interactions have similarly been a principal focus of treatment, however, the mechanistic basis of anti-platelet strategies is largely extrapolated rather than directly investigated in ICAD. Platelet FcγRIIa expression has been identified as a potent risk factor in cardiovascular disease, as elevated expression markedly increases the risk of recurrent events. Differential activation of the platelet FcγRIIa receptor may also explain the variable response of individual patients to anti-platelet medications. We review existing data on endothelial shear stress and potential interactions with the platelet FcγRIIa receptor that may alter the evolving impact of ICAD, based on local pathophysiology at the site of arterial stenosis. Current methods for quantification of endothelial shear stress and platelet activation are described, including tools that may be readily adapted to the clinical realm for further understanding of ICAD.

Influence of Lipid Excipients on Platelet Function and the Pharmacodynamic Effects of Aspirin.

ABSTRACT: The combination of pharmaceutical lipid excipients with aspirin in a novel liquid oral formulation (Vazalore) limits gastrointestinal toxicity of aspirin. This study was performed to determine whether the lipid excipients influence the pharmacodynamic effects of aspirin and whether the excipients directly affect platelet function. The pharmacodynamic effects of aspirin were assessed over a range of concentrations designed to exert limited to maximal inhibition of cyclooxygenase-1 (COX1) necessary for thromboxane A2 production. Platelet aggregation induced by arachidonic acid and assessed with the use of light transmission aggregometry was used as a direct measure of the inhibition of COX1 by aspirin. Flow cytometry was used to assess the direct effect of excipients on platelet function. Twice the ratio of lipid excipient to aspirin used in the formulation of the novel oral agent was used. Blood was taken from 20 healthy subjects and anticoagulated with trisodium citrate (3.2%, 1:10 vol/vol). Aspirin and excipients were added in vitro and incubated for 10 minutes before performance of light transmission aggregometry and flow cytometry. The excipients did not limit the pharmacodynamic effects of aspirin. When the extent of inhibition of platelet aggregation was limited, the excipients tended to enhance pharmacodynamic effects. The excipients did not activate platelets in the absence of agonist and did not alter activation of platelets in response to adenosine diphosphate, arachidonic acid, thrombin, or convulxin (a collagen mimetic). Lipid excipients used in an oral formulation of aspirin do not impair the pharmacodynamic effects of aspirin and do not alter platelet function.

Assessment of Cardiovascular Risk by the Combination of Clinical Risk Scores Plus Platelet Expression of FcγRIIa.

Platelet expression of FcγRIIa was quantified after myocardial infarction (MI) and we found that patients with high platelet FcγRIIa expression (>11,000/platelet) had a fourfold greater risk of subsequent MI, stroke, and death. This analysis of the original cohort of 197 patients was designed to determine whether platelet expression of FcγRIIa could be used in combination with clinical risk scores (GRACE [Global Registry of Acute Coronary Events] and DAPT [Dual Antiplatelet Therapy]) to refine cardiovascular risk assessment. Platelet expression of FcγRIIa quantified with the use of flow cytometry was broadly distributed in patients stratified into high and low risk groups based on clinical risk scores. In patients identified as high risk by the GRACE score, 62% had high platelet FcγRIIa expression. Similarly, in patients identified as high risk by DAPT, 55% had high platelet FcγRIIa expression. High platelet FcγRIIa expression discriminated high and low risk cohorts in patients with high cardiovascular risk defined by either the GRACE score (high platelet FcγRIIa 18.9% vs low platelet FcγRIIa 0%; odds ratio = 15.7, p = 0.06) or the DAPT score (high platelet FcγRIIa 15.4% vs low platelet FcγRIIa 3.7%; odds ratio = 5.6, p = 0.03) assessment. Platelet expression of FcγRIIa merits additional study to determine whether low platelet FcγRIIa expression can be used to guide early transition to aspirin monotherapy and high platelet FcγRIIa expression can be used to guide continuation of DAPT.

BARI 2D: A Reanalysis Focusing on Cardiovascular Events.

OBJECTIVE: To reanalyze the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial using a new composite cardiovascular disease (CVD) outcome to determine how best to treat patients with type 2 diabetes mellitus and stable coronary artery disease. PATIENTS AND METHODS: From January 1, 2001, to November 30, 2008, 2368 patients with type 2 diabetes mellitus and angiographically proven coronary artery disease were randomly assigned to insulin-sensitizing (IS) or insulin-providing (IP) therapy and simultaneously to coronary revascularization (REV) or no or delayed REV (intensive medical therapy [MED]), with all patients receiving intensive medical treatment. The outcome of this analysis was a composite of 8 CVD events. RESULTS: Four-year Kaplan-Meier rates for the composite CVD outcome were 35.8% (95% CI, 33.1%-38.5%) with IS therapy and 41.6% (95% CI, 38.7%-44.5%) with IP therapy (P=.004). Much of this difference was associated with lower in-trial levels of fibrinogen, C-reactive protein, and hemoglobin A1c with IS therapy. Four-year composite CVD rates were 32.7% (95% CI, 30.0%-35.4%) with REV and 44.7% (95% CI, 41.8%-47.6%) with MED (P<.001). A beneficial effect of IS vs IP therapy was present with REV (27.7%; 95% CI, 24.0%-31.4% vs 37.5%; 95% CI, 33.6%-41.4%; P<.001), but not with MED (43.6%; 95% CI, 39.5%-47.7% vs 45.7%; 95% CI, 41.6%-49.8%; P=.37) (homogeneity, P=.05). This interaction between IS therapy and REV was limited to participants preselected for coronary artery bypass grafting (CABG). The lowest composite CVD rates occurred in patients preselected for CABG and assigned to IS therapy and REV (17.3%; 95% CI, 11.8%-22.8%). CONCLUSION: In the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial, the IS treatment strategy and the REV treatment strategy each reduces cardiovascular events. The combination of IS drugs and CABG results in the lowest risk of subsequent CVD events. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00006305.

Surveillance and Management of Troponin Elevation after Vascular Surgery.

BACKGROUND: Postopertive troponin elevation may occur without typical or atypical cardiac symptoms and is associated with an increased 30-day morbidity and mortality. The objective of the study was to implement a quality improvement initiative of postoperative troponin surveillance algorithm aimed at intensifying medical management after vascular surgery. METHODS: We conducted a single-center study of postoperative troponin surveillance after vascular surgery (n = 201) at a tertiary care, academic medical center from January to December 2016. Troponin surveillance was performed on postoperative days 1-3 after carotid endarterectomy, endovascular aortic repair, infrainguinal bypass, open abdominal aortic aneurysm repair, peripheral vascular intervention, and suprainguinal bypass, regardless of cardiac symptoms. Patients with troponin I elevation (>0.034 ng/mL) were managed with a treatment algorithm which included single or dual antiplatelet (AP) agent, high-intensity statin therapy, smoking cessation consultation, and outpatient cardiology consultation and stress testing. Patients with troponin elevation ≥1.0 ng/mL received inpatient cardiology consultation. We assessed adherence to the protocol for intensification of best medical therapy defined as high-dose statin therapy, increase in AP therapy, and smoking cessation consultation according to the established algorithm. RESULTS: Troponin elevation was recorded in 17% (34/201) of patients and was associated with cardiac symptoms in 8 patients (24%), while 26 (76%) patients had an asymptomatic abnormal troponin on postoperative surveillance. One patient was excluded due to death immediately after SUPRA, resulting in 200 patients. Troponin elevation ≥1.0 ng/mL occurred in 11 asymptomatic patients (5.5%). Any intensification of medical therapy was instituted in 76% of patients with elevated troponin and included high-intensity statin therapy (58%), increase in AP therapy (18%), and smoking cessation consultation (66%). Once an elevated troponin level was recognized, 52% of our patients received cardiology consultation with an increased likelihood (100%) in patients with troponin ≥1 ng/mL (P < 0.001). Adherence to outpatient stress testing was 66%. Intensification of medical therapy was not significantly different between patients with abnormal troponin values, >0.034-1.0 (n = 23) versus ≥1.0 ng/mL (n = 10); statin therapy (P = 1.0), AP (P = 0.34), and smoking cessation (P = 1.0). One-year mortality was higher in patients with postoperative troponin elevation than those with normal postoperative troponin levels (12% vs. 2.4%; P = 0.03). CONCLUSIONS: Routine postoperative troponin surveillance results in intensification of statin therapy in patients with asymptomatic troponin elevation. Further study is needed to determine if this approach reduces long-term cardiovascular morbidity and mortality.