Ex Vivo Antiplatelet Effects of Oral Anticoagulants.

BACKGROUND: The impact of non-vitamin K antagonist oral anticoagulants (NOACs) on platelet function is still unclear. We conducted a comprehensive ex vivo study aimed at assessing the effect of the four currently marketed NOACs on platelet function. METHODS: We incubated blood samples from healthy donors with concentrations of NOACs (50, 150 and 250 ng/mL), in the range of those achieved in the plasma of patients during therapy. We evaluated generation of thrombin; light transmittance platelet aggregation (LTA) in response to adenosine diphosphate (ADP), thrombin receptor-activating peptide (TRAP), human γ-thrombin (THR) and tissue factor (TF); generation of thromboxane (TX)B2; and expression of protease-activated receptor (PAR)-1 and P-selectin on the platelet surface. RESULTS: All NOACs concentration-dependently reduced thrombin generation compared with control. THR-induced LTA was suppressed by the addition of dabigatran at any concentration, while TF-induced LTA was reduced by factor-Xa inhibitors. ADP- and TRAP-induced LTA was not modified by NOACs. TXB2 generation was reduced by all NOACs, particularly at the highest concentrations. We found a concentration-dependent increase in PAR-1 expression after incubation with dabigatran, mainly at the highest concentrations, but not with FXa inhibitors; P-selectin expression was not changed by any drugs. CONCLUSIONS: Treatment with the NOACs is associated with measurable ex vivo changes in platelet function, arguing for antiplatelet effects beyond the well-known anticoagulant activities of these drugs. There are differences, however, among the NOACs, especially between dabigatran and the FXa inhibitors.

Effects of a novel nutraceutical combination (BruMeChol™) in subjects with mild hypercholesterolemia: study protocol of a randomized, double-blind, controlled trial.

BACKGROUND: Elevated cholesterol levels and systemic inflammation are considered relevant risk factors for cardiovascular disease (CVD) development and progression. Increasing evidence suggests that cholesterol-lowering and inflammation-lowering nutraceuticals are useful in the management of moderate hypercholesterolemia. Here, we describe the study protocol of a clinical trial aimed to evaluate the cholesterol and inflammatory lowering effect of an innovative dietary supplement (BruMeChol™, Mivell S.r.l., Italy), composed of a mixture of extracts of bergamot and olive fruits in association with vitamin K2 in subjects with mild hypercholesterolemia. METHODS: The study was planned as a randomized, double-blind, placebo-controlled, parallel group clinical trial for 12 weeks at the Cardiology Unit of the IRCCS INRCA of Ancona, Italy. A total of 125 subjects (age ≥ 40 years) with mild hypercholesterolemia (total serum cholesterol levels ≥ 200 and ≤ 250 mg/dl) will be recruited. Intervention arm participants will take one capsule of dietary supplement two times a day, 15 min before the main meal. Control arm participants will receive one capsule of placebo in the same way. The dietary supplement capsule contains the following ingredients: phytosterols, flavonoid-rich extract of bergamot fruit (Citrus bergamia), flavonoid-rich extract of olive fruit (Olea europaea), and vitamin K2. Participants will undergo a medical evaluation and chemical-clinical examinations, which include lipid profile, glycemia, biomarkers of renal, liver and cardiac/muscular functions, interleukins (IL 6, IL-32, IL-37, and IL-38), and innovative mediators of inflammation such as inflamma-miRs (miR-21 and miR-146a), at baseline, and after 6 and 12 weeks of treatment. The decrease in total cholesterol levels and inflammatory biomarkers will be the primary and secondary endpoints of the study. DISCUSSION: This protocol study, planned to verify the effects of BruMeChol™ dietary supplementation in subjects with mild hypercholesterolemia, could also contribute to new study designs for next large-scale multicenter clinical trials. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12619000170123 . Retrospectively registered on 5 February 2019.

Clustering of ABCB1 and CYP2C19 Genetic Variants Predicts Risk of Major Bleeding and Thrombotic Events in Elderly Patients with Acute Coronary Syndrome Receiving Dual Antiplatelet Therapy with Aspirin and Clopidogrel.

OBJECTIVE: The clinical efficacy of clopidogrel in secondary prevention of vascular events is hampered by marked inter-patient variability in drug response, which partially depends on genetic make-up. The aim of this pilot prospective study was to evaluate 12-month cardiovascular outcomes in elderly patients with acute coronary syndrome (ACS) receiving dual antiplatelet therapy (aspirin and clopidogrel) according to the clustering of CYP2C19 and ABCB1 genetic variants. METHODS: Participants were 100 consecutive ACS patients who were genotyped for CYP2C19 (G681A and C-806T) and ABCB1 (C3435T) polymorphisms, which affect clopidogrel metabolism and bioavailability, using PCR-restriction fragment length polymorphism. They were then grouped as poor, extensive and ultra-rapid metabolisers based on the combination of CYP2C19 loss-of-function (CYP2C19*2) and gain-of-function (CYP2C19*17) alleles and ABCB1 alleles. The predictive value of each phenotype for acute vascular events was estimated based on 12-month cardiovascular outcomes. RESULTS: The poor metabolisers were at an increased risk of thrombotic events (OR 1.26; 95% CI 1.099-1.45; χ2 = 5.676; p = 0.027), whereas the ultra-rapid metabolisers had a 1.31-fold increased risk of bleeding events compared with the poor and extensive metabolisers (OR 1.31; 95% CI 1.033-1.67; χ2 = 5.676; p = 0.048). Logistic regression model, including age, sex, BMI and smoking habit, confirmed the differential risk of major events in low and ultra-rapid metabolisers. CONCLUSIONS: Our findings suggest that ACS patients classified as 'poor or ultra-rapid' metabolisers based on CYP2C19 and ABCB1 genotypes should receive alternative antiplatelet therapies to clopidogrel.

Platelet function and long-term antiplatelet therapy in women: is there a gender-specificity? A 'state-of-the-art' paper.

Although the female gender is generally less represented in cardiovascular studies, observational and randomized investigations suggest that-compared with men-women may obtain different benefits from antiplatelet therapy. Multiple factors, including hormonal mechanisms and differences in platelet biology, might contribute to such apparent gender peculiarities. The thrombotic and bleeding risks, as well as outcomes after a cardiovascular event, appear to differ between genders, partly in relation to differences in age, comorbidities and body size. Equally, the benefits of antiplatelet therapy may differ in women compared with men in different vascular beds, during primary or secondary prevention and according to the type of an antiplatelet agent used. This document is an attempt to bring together current evidence, clinical practices and gaps of knowledge on gender-specific platelet function and antiplatelet therapy. On the basis of the available data, we provide suggestions on current indications of antiplatelet therapy for cardiovascular prevention in women with different clinical features; no strong recommendation may be given because the available data derive from observational studies or post hoc/subgroup analyses of randomized studies without systematic adjustments for baseline risk profiles.

A fast and effective method to assess myocardial hyperemia in acute myocarditis by magnetic resonance.

Current cardiac magnetic resonance (CMR) quantitative signs for the diagnosis of myocarditis include myocardial edema, fibrosis and myocardial hyperemia (Hyp). Methods for the assessment of Hyp are actually complex and time-consuming. To test a simple and fast method to assess Hyp, using contrast enhancement steady state free precession (ceSSFP) technique. CMR imaging at 1.5T was performed on 39 patients with diagnosis of acute myocarditis and in 20 healthy controls. Hyp was evaluated in systolic and diastolic frames (Hyp-SYS and Hyp-DIA) as areas of myocardial hyperintensity in ceSSFP images early after gadolinium injection. Myocardial edema was evaluated using T2-STIR images. Myocardial fibrosis was assessed in conventional late gadolinium enhancement (LGE) images. A value of ≤12.1 g of Hyp-DIA was obtained as cut-off of normality in healthy controls. Using this threshold, Hyp was detected in 30 patients (77 %) with myocarditis. LGE was detected in 36 patients (92 %), and myocardial edema in 38 (97 %) patients with myocarditis A linear relation was found between Hyp-DIA and the extent of myocardial edema (R(2) 0.48, 95 % CI 0.47-0.85, p < 0.001) and the extent of LGE (R(2) 0.41, 95 % CI 0.31-0.61, p < 0.001). Patients with hyperemia had higher levels of C-reactive protein (p < 0.001), a higher extent of LGE (p < 0.05) and a larger left atrial area (p < 0.05). ceSSFP sequence at CMR is a novel and fast method to assess myocardial hyperemia in patient with acute myocarditis. Compared with non-Hyp subjects, patients with Hyp had more signs of inflammation and myocardial damage.

Inconsistency of different methods for assessing ex vivo platelet function: relevance for the detection of aspirin resistance.

BACKGROUND: Assays to evaluate platelet function are often interchangeably used to assess "resistance" to aspirin. We compared different platelet function assays in patients treated or untreated with aspirin. DESIGN AND METHODS: Platelet function was evaluated in 162 subjects, 85 of whom were not being treated with any antiplatelet drug and 77 of whom were receiving chronic therapy with low-dose aspirin. Platelet Function Analyzer collagen/ADP- and collagen/epinephrine closure times, as well as light transmittance aggregometry in response to ADP, collagen and arachidonic acid (this last in 47 aspirin-treated patients) were determined. In 43 aspirin-treated patients, serum thromboxane B(2) levels were also measured. RESULTS: In untreated patients, collagen/ADP- and collagen/epinephrine-closure times were correlated with each other (r=0.5, P=0.0001), but did not correlate with ADP- or collagen-induced aggregation. In patients treated with aspirin, collagen/ADP-closure time values were not different from those in untreated patients, while the collagen/epinephrine-closure time was prolonged. ADP-induced aggregation was unaffected by aspirin, while collagen-induced aggregation was reduced. Arachidonic acid-induced aggregation was almost completely suppressed (% maximum light transmittance aggregometry =5 ± 13%). There was, however, no correlation between the various platelet function tests. Serum thromboxane B(2), an index of platelet cyclooxygenase-1 activity, was almost completely suppressed (down to 8 ± 17 ng/mL) in treated patients, and was not correlated with arachidonic acid-, ADP- and collagen-induced aggregation or with collagen/ADP-closure time, but was inversely correlated with collagen/epinephrine-closure time. CONCLUSIONS: There is a high heterogeneity of results of tests evaluating inhibition of platelet function by aspirin, and the results of functional tests do not match biochemical measurement of cyclooxygenase-1 activity. Extreme caution should, therefore, be used in defining "resistance" to aspirin on the basis of the results of these tests.