Charlotte Grosdidier

Human CalDAG-GEFI gene (RASGRP2) mutation affects platelet function and causes severe bleeding.

First case of a human RASGRP2 mutation affecting Rap1 activation in platelets and causing severe bleeding.

Effect of CYP2C19*2 and *17 Genetic Variants on Platelet Response to Clopidogrel and Prasugrel Maintenance Dose and Relation to Bleeding Complications

The present study was performed to compare the influence of cytochrome P459 2C19 (CYP2C19) *2 and *17 genetic variants on the platelet response to clopidogrel and prasugrel maintenance therapy and to assess the relation between platelet reactivity and bleeding complications. A total of 730 patients were included (517 patients treated with clopidogrel 150 mg/day and 213 discharged with prasugrel 10 mg). Platelet reactivity was assessed at 1 month with the platelet reactivity index vasodilator-stimulated phosphoprotein (PRI VASP). High on-treatment platelet reactivity was defined as PRI VASP >50% and low on-treatment platelet reactivity (LTPR) as PRI VASP <20%. The patients were classified according to their genotypes as poor metabolizers (*2/non *17), intermediate metabolizers (*2/*17 or non *2/non *17) and ultrametabolizers (non *2/*17). At 1 month, the prasugrel response was significantly better than the clopidogrel response in all groups of patients, with a lower incidence of high on-treatment platelet reactivity but a greater incidence of LTPR, regardless of the genetic variants. The genetic distribution had a significant effect on the mean PRI VASP values, the incidence of high on-treatment platelet reactivity, and LTPR with both clopidogrel and prasugrel (p <0.05 for all). LTPR identified a group of patients at a greater risk of bleeding (odds ratio 4.8, 95% confidence interval 2.7 to 8.3; p <0.0001). In conclusion, the present study showed that both clopidogrel and prasugrel have genetic modulation by CYP2C19 *2 and *17 alleles and that prasugrel provides greater platelet inhibition, regardless of the genotypes. In addition, LTPR was associated with a greater risk of bleeding.

Factors associated with the failure of clopidogrel dose-adjustment according to platelet reactivity monitoring to optimize P2Y12-ADP receptor blockade

INTRODUCTION Inter-individual variability in clopidogrel responsiveness is dependent on genetic polymorphisms. We aimed to investigate the impact of 3 genetic polymorphisms involved in clopidogrel metabolism on a strategy of dose-adjustment according to platelet reactivity (PR) monitoring. MATERIAL AND METHODS [corrected] This prospective multicenter study enrolled 498 ACS patients undergoing PCI. PR was measured using the Vasodilator-Stimulated Phosphoprotein index (VASP) and a cut-off value of ≥50% defined high on-treatment platelet reactivity (HTPR). Genetic polymorphisms of cytochrome (CYP) 2C19, Paraxonase-1 (PON1) and ABCB1 were determined by allele specific PCR. Dose-adjustment was performed using up-to 3 additional loading doses (LD) of 600mg clopidogrel in order to obtain a VASP <50% in patients with HTPR following the first LD. RESULTS CYP 2C19 2*polymorphism (p=0.02), but neither PON1 (p=0.8) nor ABCB1 genotype (p=0.9), was significantly associated with HTPR. The dose-adjustment strategy failed in 11% of patients. ABCB1 polymorphism was significantly associated with a failed dose-adjustment (FDA) (p=0.04). No relation was found between the other genotypes and the efficacy of LD adjustment. In multivariate analysis, BMI and ABCB1 polymorphism were the only factors significantly associated with FDA (p=0.005 and p=0.04 respectively). CONCLUSION While CYP 2C19 2* is associated with HTPR after 600mg of clopidogrel, ABCB1 is responsible for the failure of a strategy of loading dose-adjustment according to PR monitoring. These findings may help to define a therapeutic strategy to optimize anti-platelet therapy in ACS patients undergoing PCI.

Safety and effectiveness of the association ezetimibe-statin (E-S) versus high dose rosuvastatin after acute coronary syndrome: the SAFE-ES study.

BACKGROUND Statin therapy is a cornerstone therapy for secondary prevention after acute coronary syndrome (ACS). However, the use of these drugs can be limited by side effects, mainly muscular pain. Ezetimibe is a newer lipid-lowering agent, with fewer side effects. AIMS The present study was designed to compare a commercially available association of ezetimibe and simvastatin (E-S) to high dose Rosuvastatin on cholesterol and muscular enzyme levels and occurrence of muscular pain. METHODS All consecutive ACS statin-naïve patients with LDL cholesterol (LDL-C)>100mg/dL randomly received either high dose statin (Rosuvastatin 20mg) or E-S 10/40-mg. All patients had one-month follow-up with biological testing and clinical examination. We compared the two groups on the biological efficiency and incidence of muscular pain. RESULTS One hundred and twenty-eight patients were randomized; 64 received E-S and 64 Rosuvastatin. In the two groups, the lowering of LDL-C level (Δ=51%) at one month was significant (P<0.01) without any difference in the rate of lowering on LDL-C or HDL-C suggesting that E-S is as effective as high dose Rosuvastatin (P=0.77 and P=0.99). The rate of patients reaching the objective of LDL-C<100mg/dL (45%) and LDL-C<70mg/dL (51%) was not different in the two clusters (P=0.65). Incidence of muscular pain was 15% higher in patients treated with Rosuvastatin (P=0.01) without any difference on CPK level (P=0.6). CONCLUSION Using an association of E-S in an effective alternative strategy to high dose Rosuvastatin with a lower incidence of muscular pain, which might impact adherence to medication after ACS.

Diagnostic de l’ovalocytose du Sud-Est asiatique : nécessité d’une observation attentive des constantes érythrocytaires et du frottis sanguin

Southeast asian ovalocytosis (SAO) is characterized by macro-ovalocytes and ovalo-stomatocytes on blood smear. SAO is common in Malaisia and Papua-New-Guinea where upwards to 40 per cent of the population is affected in some coastal region. Inherited in an autosomal dominant way, illness results from deletion of codons 400-408 in SLC4A1 gene which encodes for band 3 erythrocyte membrane protein. This deletion is responsible for an unusual erythrocyte stiffness and oval shape of the cells on blood smear. Heterozygous carriers are usually asymptomatic whereas homozygous are not viable without an intensive antenatal care. Here, we describe 4 patients diagnosed incidentally by cytogram appearance of the Advia® 2120i (Siemens) representing hemoglobin concentration according to red blood mean cellular volume (GR/VCH).

Is platelet inhibition correlated with time from last intake on P2Y12 blockers after an acute coronary syndrome? A pilot study

Abstract Delay from the last intake of drug could be an important and unexplored variable in the biological response to antiplatelet agents after acute coronary syndrome (ACS) discharge. The objective was to define the impact of the delay from P2Y12 blocker intake on the platelet inhibition level. We compared ticagrelor-, prasugrel-, and clopidogrel-treated patients. All consecutive patients, who had been addressed between 2013 and 2014 for ACS, treated with aspirin and a P2Y12 blocker as maintenance dose, were eligible. One month after discharge, blood sample and a questionnaire were proposed to the patient by a nurse blinded to the protocol. On this questionnaire, three questions about name of the drug, regularity of the intakes, and hour of the last intake were collected. The response to antiplatelet therapy was assessed using platelet reactivity index vasodilator-stimulated phosphoprotein (PRI VASP) and % of adenosine-5’-diphosphate-induced aggregation (%ADP).The primary objective of this study was to evaluate the correlation between platelet inhibition and delay from drug intake. We enrolled 474 ACS treated with clopidogrel 75 mg in 182 cases (38% patients), prasugrel in 190 cases (40%), or ticagrelor in 102 patients (22%). We observed a significant correlation between delay from intake and PRI VASP and %ADP for ticagrelor (r = 0.25, p = 0.01; r = 0.21, p = 0.03; respectively). On clopidogrel (r = 0.09, p = 0.24; r = 0.02, p = 0.80; respectively) and prasugrel (r = 0.02, p = 0.82; r = 0.11, p = 0.12 respectively), no correlation exists. In conclusion, ticagrelor, unlike thienopyridines, is associated with a significant correlation between delay from the last intake and platelet inhibition.

0010: Impact of thienopyridines on platelet CD40L biodisponibility after an acute coronary syndrome in relation with bleeding events

Background CD40 Ligand (CD40L) is expressed on platelets upon ADP stimulation and is involved in haemostasis. CD40L deficient mice exhibit thrombus instability and increased bleeding time. Methods We investigated the relationships between plasma and platelet-associated CD40L, ADP signaling and bleeding event occurrence in patients receiving thienopyridines one month after a stented Acute Coronary Syndrome (ACS). Basal platelet CD40L surface expression (pCD40L), pCD40L after PAR-1 agonist stimulation (TRAP pCD40L) and platelet released CD40L (rCD40L) were quantified. Results were compared to VASP as a measure of P2Y12 inhibition level. Results We included 318 patients between November 2012 and June 2014. Thienopyridines treated patients exhibit low pCD40L, TRAP pCD40L and rCD40L in comparison with controls. pCD40L and rCD40L were correlated with PRI-VASP. Thienopyridine treatment strongly reduces rCD40L. Hyperesponder to thienopyridine status is associated with high levels of TRAP pCD40L. pCD40L and TRAP pCD40L levels are reduced in the bleeding cohort. In multivariate analysis pCD40L significantly contributes to bleeding risk independently of PRI-VASP. Conclusion pCD40L and rCD40L levels are reduced by thienopyridines. pCD40L associates with the bleeding risk independently of the VASP levels and may represent a novel target to assess bleeding risk in thienopyridine-treated ACS patients.