Chronic kidney disease status modifies the association of CYP2C19 polymorphism in predicting clinical outcomes following coronary stent implantation

Introduction

There is some controversy regarding the effect of CYP2C19 polymorphism on clinical outcome in patients with dual antiplatelet therapy. Chronic kidney disease (CKD) is associated with increased risk of cardiovascular event, but the association between the possession of CYP2C19 loss-of-function (LOF) alleles and clinical outcome according to the presence of CKD is poorly understood. The aim of this study was to investigate whether CKD status modifies the association of CYP2C19 polymorphism in predicting outcomes in a prospective cohort study.

Material and Methods

We enrolled 331 patients following coronary stent implantation. Patients were divided into two groups: CKD (n = 154) and non-CKD (n = 177). Platelet reactivity and CYP2C19 polymorphism were examined. The subjects were further divided into two groups according to the possession of CYP2C19 LOF alleles: carriers and non-carriers. Patients were followed up and clinical events were evaluated according to CKD and carrier status.

Results

The proportion of high platelet reactivity was significantly higher in carriers than in non-carriers in both CKD (42.4% versus 21.7%; P = 0.016) and non-CKD groups (34.3% versus 3.7%; P < 0.001). In the non-CKD group alone, the incidence of cardiovascular events was significantly higher in carriers than in non-carriers (13.7% versus 1.7%; P = 0.013). Kaplan-Meier analysis demonstrated a significantly higher probability of cardiovascular events in carriers than in non-carriers in the non-CKD group (log-rank test: P = 0.013) and there was no significant difference in the CKD group (log-rank test: P = 0.591). Multivariate analysis identified carriers as an independent predictor of cardiovascular events only in the non-CKD group alone (hazard ratio: 8.048; 95% confidence interval: 1.066 to 60.757; P = 0.043).

Conclusions

CYP2C19 polymorphism significantly correlates with clinical outcome in non-CKD patients, and CKD status modifies the association of CYP2C19 polymorphism in predicting clinical outcomes following coronary stent implantation.     

Impact of CYP2C19 Polymorphism and Proton Pump Inhibitors on Platelet Reactivity to Clopidogrel and Clinical Outcomes Following Stent Implantation

Background

The response to clopidogrel, and some kind of the drug interaction are multifactorial.

Methods and Results

We enrolled 174 consecutive patients and determined CYP2C19 genotypes, measured platelet aggregation, and assessed the relationship between CYP2C19 genotype and platelet reactivity 24 hours after clopidogrel administration, and the risk of cardiovascular events over 18 months follow-up. A sub analysis examined the impact of rabeprazole, a proton pump inhibitor (PPI) less affected by CYP2C19.The CYP2C19 genotype was extensive metabolizer (EM) in 36%, intermediate metabolizer (IM) in 45%, and poor metabolizer (PM) in 19%. Platelet reactivity was significantly lower in the EM group than in the IM and PM groups (EM, IM, PM: 3560 ± 1404, 4203 ± 1302, 5084 ± 1007 AU•min, P < 0.05). The cardiovascular event rate was higher in the IM and PM groups than in the EM group (12.7% and 12.5% vs 1.6%; Hazard ratio for IM 10.6, P = 0.029; for PM 11.3, P = 0.040). No differences were seen between patients taking (N = 50) and not taking (N = 124) rabeprazole in residual platelet aggregation (4407 ± 1360 vs 4048 ± 1394, AU•min, P = 0.2782), or in cardiovascular events (10.0% vs 8.1%, HR 0.97, P = 0.97).

Conclusions

CYP2C19 genotype is associated with an increased risk of cardiovascular events following stent implantation in Japanese patients.     

VASP phosphorylation and genetic polymorphism for clopidogrel resistance in Chinese patients with non-cardioembolic ischemic stroke

Background

Clopidogrel resistance(CR)is found in non-cardioembolic ischemic stroke (NCIS) patients. However, it is still largely unknown how to identify CR in NCIS patients by laboratory and genetic characteristics.

Methods

A total of 95 patients with acute NCIS were recruited. Phosphorylation of the vasodilator stimulated phosphoprotein (VASP) was detected using flow cytometry, and genes(CYP2C19,CYP3A4) were detected using the Sanger method. The baseline of platelet reactivity index (BPRI) before clopidogrel treatment and the platelet reactivity index with clopidogrel treatment (CPRI) for 7 days were measured. Laboratory clopidogrel resistance (LCR) was defined as CPRI of ≥ 50%.Clinical clopidogrel resistance (CCR) was defined as the presence of progressive stroke during hospitalization, stroke recurrence or occurrence of other ischemic vascular events within 6 months.

Results

The incidence of LCR was 41.05% and 18.95% developed CCR. The incidence of LCR was significantly higher in GA/AA patients with CYP2C19 (681G > A) (χ2 = 11.16, P = 0.001) and CYP2C19 (636G > A) (χ2 = 4.829, P = 0.028) than in wildtype GG patients. CYP2C19 (681G > A) (OR 6.272, 95%CI 2.162,18.199,P = 0.001) and CYP2C19 (636G > A) (OR: 5.625,95%CI 1.439, 21.583,P = 0.013) were risk factors for LCR. patients with LCR were more likely to develop CCR (χ2 = 6.021, P = 0.014). The probability of CCR was markedly increased in GA/AA patients with CYP2C19 (681G > A) (χ2 = 10.341, P = 0.001). We identified CYP2C19 (681G > A) (OR 7.814, 95%CI 1.816, 33.618 P = 0.006), Essen score (OR 8.351, 95%CI 1.848, 37.745 P = 0.006), and LCR (OR 5.881, 95%CI 1.373, 25.192, P = 0.017) as risk factors for CCR.

Conclusion

In clinical practice,LCR and CYP2C19 gene polymorphism should be assessed in NCIS patients receiving clopidogrel treatment.The Chinese Clinical Trial Registry number: ChiCTR-ONC-13003406     

Impact of the proton pump inhibitors and CYP2C19*2 polymorphism on platelet response to clopidogrel as assessed by four platelet function assays

Background

Previous studies suggested a possible negative interference of proton pump inhibitors (PPIs) on clopidogrel’s antiplatelet effect because of the competitive inhibition of the CYP 2C19 isoenzyme. Moreover, carriers of the loss-of-function allele of CYP2C19 polymorphism (CYP2C19*2) display significantly lower responses to clopidogrel. In this study, we investigated the association between CYP2C19*2 genotype, PPI intake and clopidogrel resistance in patients with coronary artery disease (CAD) and their effect on clinical outcome.

Methods

We recruited 95 patients with CAD receiving chronic clopidogrel therapy in combination with aspirin. Platelet reactivity was simultaneously assessed by INNOVANCE PFA-100 P2Y, ADP-induced light transmission aggregometry (LTA), flow-cytometric vasodilator-stimulated phosphoprotein (VASP)-phosphorylation assay and multiple electrode aggregometry (Multiplate). Cardiovascular outcomes were recorded during 1-year follow-up period.

Results

Only platelet reactivity assessed by measuring platelet phosphorylated-VASP demonstrated a significant higher platelet reactivity in carriers of CYP2C19*2 (p = 0.023). The other methods displayed higher - but not statistically significant - platelet reactivity in patients carrying the CYP2C19*2 variant as compared with non-carriers. Patients on PPIs demonstrated almost similar suppression of platelet reactivity in comparison with those not treated with PPIs by all platelet function assays. In logistic regression analysis none of the platelet function assays measurements were related with clinical outcomes. Similarly neither CYP2C19*2 genetic variant nor PPI treatment were associated with adverse clinical events.

Conclusions

PPI co-administration did not influence clopidogrel’s antiplatelet effect on laboratory testing by all platelet function assays used. On the contrary, patients carrying CYP2C19*2 genotype had significantly higher residual platelet reactivity as estimated by VASP-phosphorylation assay.     

Influence of cytochrome 2C19 allelic variants on on-treatment platelet reactivity evaluated by five different platelet function tests

Background

The antiplatelet effect of clopidogrel has been linked to cytochrome P450 2C19 (CYP2C19) carrier status. The presence of loss of function and gain of function variants were found to have a gene-dose effect on clopidogrel metabolism. However, genotyping is only one aspect of predicting response to clopidogrel and several platelet function tests are available to measure platelet response.Patients and methodsWe studied the influence of CYP2C19 allelic variants on on-treatment platelet reactivity as assessed by light transmission aggregometry (LTA), the VerifyNow P2Y12 assay, the VASP assay, multiple electrode aggregometry (MEA), and the Impact-R in 288 patients after stenting for cardiovascular disease. Allelic variants of CYP2C19 were determined with the Infiniti® CYP450 2C19 + assay and categorized into four metabolizer states (ultrarapid, extensive, intermediate, poor).

Results

Platelet reactivity increased linearly from ultrarapid to poor metabolizers using the VerifyNow P2Y12 assay (P = 0.04), the VASP assay (P = 0.02) and the Impact-R (P = 0.04). The proportion of patients with high on-treatment residual platelet reactivity (HRPR) identified by LTA, the VerifyNow P2Y12 assay and the VASP assay increased when the metabolizer status decreased, while no such relationship could be identified for results of MEA and Impact-R. The presence of loss of function variants (*2/*2, *2-8*/wt, *2/*17) was an independent predictor of HRPR in LTA and the VASP assay while it did not reach statistical significance in the VerifyNow P2Y12 assay, MEA, and the Impact-R.

Conclusion

Depending on the type of platelet function test differences in the association of on-treatment platelet reactivity with CYP2C19 carrier status are observed.     

Relationship Between ABCB1 Polymorphisms,Thromboelastography and Risk of Bleeding Events in Clopidogrel-Treated Patients With ST-Elevation Myocardial Infarction

Introduction

This study sought to investigate the relationship of polymorphisms in ABCB1 and the predictive value of thromboelastography (TEG) on bleeding risk in clopidogrel-treated patients with ST-elevation myocardial infarction (STEMI).

Methods

467 consecutive patients with STEMI undergoing percutaneous coronary intervention (PCI) were enrolled. Twenty tag single nucleotide polymorphisms (SNPs) selected from ABCB1 gene and CYP2C19*2, *3, *17 were detected by the ligase detection reaction. Platelet reactivity was assessed by TEG. The follow-up period was 12 months.

Results

By receiver operating characteristic curve analysis, the TEG platelet mapping assay value of ADP inhibition had the best predictive value of bleeding academic research consortium definition (BARC) ≥ 3b bleedings, yielding an area under the curve (AUC) of 0.707 (95% CI 0.662-0.749, p = 0.009; cut-off value > 93.4%). ADP inhibition can also predict BARC ≥ 3 bleedings with an AUC of 0.594 (95% CI 0.546-0.640, p = 0.05; cut-off value > 92.5%). After adjustment for established risk factors of bleeding including the gain of function CYP2C19*17 allele, age, female gender, renal function, the multivariable logistic regression model demonstrated that ADP inhibition > 92.5% (OR 2.247, 95%CI 1.082-4.665, P = 0.03), carriage of rs1045642 (OR 2.943, 95%CI 1.195-7.247, P = 0.019) and rs7779562 (OR 0.453, 95%CI 0.219-0.936, P = 0.032) were independent predictors of BARC ≥ 3 bleedings. These associations were validated in a second cohort of 504 STEMI patients.

Conclusions

In STEMI patients treated with clopidogrel after PCI, the ABCB1 tag SNP rs1045642 is associated with higher risk of bleedings while rs7779562 is associated with lower bleeding risk, and ADP inhibition in TEG has a predictive value of bleedings.     

Genetic and non-genetic factors responsible for antiplatelet effects of clopidogrel in Japanese patients undergoing coronary stent implantation: An algorithm to predict on-clopidogrel platelet reactivity

Introduction

Antiplatelet effects of clopidogrel appear to be affected by various factors including genetic polymorphism. So far, there has been little information about the response of clopidogrel in Asians, whose prevalence of a CYP2C19 loss-of-function (LOF) allele is high.

Methods and Results

We investigated background and clinical factors affecting on-clopidogrel platelet reactivity in Japanese patients undergoing coronary stent implantation (n = 114). In univariate analysis, antiplatelet effects of clopidogrel in a steady state were associated with not only CYP2C19 genotypes but also several factors including dyslipidemia. In addition, we developed an algorithm that can estimate P2Y12 Reaction Units (PRU) in a steady state by multiple regression analysis and evaluated the adequacy of the algorithm by the Akaike Information Criterion.

Conclusions

We revealed several factors influencing on-clopidogrel platelet reactivity in Japanese patients. We also succeeded in developing an algorithm that estimates PRU in a steady state, although it is uncertain whether the algorithm can be applied to other populations.     

Genetic determinants of high on-treatment platelet reactivity in clopidogrel treated Chinese patients

Introduction

Cytochrome P450 (CYP), ATP-binding cassette transporters (ABCB1), and paraoxonase-1 (PON1) play crucial roles in clopidogel absorption and bioactivation. Genetic polymorphisms in these genes have been associated with the variability of the response to clopidogrel, however their contribution to high on-treatment platelet reactivity (HPR) in clopidogrel treated Chinese patients is less known.

Materials and methods

Five-hundred Chinese-Han patients treated with clopidogrel for acute coronary syndrome (ACS) were consecutively recruited from the Department of Geriatric Cardiology, General Hospital of Chinese People’s Liberation Army, from September 2010 to September 2012. We assessed the relations of CYP2C19*2 (rs4244285), CYP2C19*3 (rs4986893), CYP2C19*17 (rs12248560), PON1Q129R (rs662) and ABCB1C3435T (rs1045642) to the platelet aggregation after 5 days maintenance dose of clopidogrel administration, and the risk for HPR. The cutoff of HPR was defined as 20 μmol/L adenosine diphosphate (ADP)-induced platelet aggregation > 50%.

Results

Both CYP2C19*2 and *3 alleles were significantly associated with higher platelet aggregation after 5 days maintenance dose of clopidogrel administration (P < 0.00001and P = 0.042, respectively). The platelet aggregation in carriers of at least one CYP2C19 loss-of-function allele (*2 or *3, accounted for 58% of the study population) was obviously higher than that in non-carriers (P < 0.00001). Patients with the CYP2C19*2 allele had a higher risk of HPR than those with the CYP2C19 wild-type genotype [adjusted hazard ratio (HR), 1.56; 95% confidence interval(CI), 1.04–2.33, P = 0.03]. The carriers of at least one CYP2C19 loss-of-function allele could also predict significantly greater risk of HPR compared with non-carriers (adjusted HR1.79,95% CI: 1.33–2.4,P = 0.003). However, the carriage of CYP2C19*3 alone could not predict the risk of HPR significantly (adjusted HR, 1.5; 95% CI: 0.83–3, P = 0.16). Significant relation of CYP2C19*17, PON1Q129R and ABCB1C3435T to the platelet aggregation was not found.

Conclusion

In clopidogrel treated Chinese patients with ACS, carriers of at least one CYP2C19 loss-of-function allele could predict greater risk of HPR, with the impact mainly attributing to CYP2C19*2. Neither ABCB1 nor PON1 genotype could influence the antiplatelet response of clopidogrel in the cohort of Chinese patients.     

ABCB1 C3435T polymorphism and risk of adverse clinical events in clopidogrel treated patients: a meta-analysis

Introduction

The ABCB1 C3435T polymorphism limits oral bioavailability of clopidogrel and may influence prognosis of patients treated with clopidogrel. Several studies have examined the association between the C3435T polymorphism and risk of adverse clinical events in clopidogrel treated patients, but the results were inconsistent. To assess the role of the C3435T polymorphism in the impact on clinical outcomes, a meta-analysis was conducted.

Methods

6 studies with 10,153 subjects were included in this meta-analysis. Fixed- or random-effects model was chosen according to heterogeneity. Publication bias was evaluated by fail-safe numbers.

Results

The association of the C3435T polymorphism with risk of overall recurrent ischemic events in clopidogrel treated patients was not statistically significant for all genetic models (OR = 1.13, 95%CI: 0.78-1.64, P = 0.51; OR = 1.15, 95%CI: 0.99-1.33, P = 0.07; OR = 1.19, 95%CI: 0.81-1.76, P = 0.37). Significant association was identified between the C3435T polymorphism and risk of short-term recurrent ischemic events (OR = 1.55, 95% CI: 1.09-2.20, P = 0.01; OR = 1.41, 95% CI: 1.06-1.87, P = 0.02; OR = 1.77, 95% CI: 1.19-2.63, P = 0.005). No statistically significant association between the C3435T polymorphism and stent thrombosis (OR = 0.79, 95% CI: 0.47-1.32, P = 0.37) or bleeding (OR = 0.98, 95% CI: 0.79-1.21, P = 0.82) was identified. The results may be affected by publication bias.

Conclusions

This meta-analysis failed to show an association between the ABCB1 C3435T polymorphism and risk of overall recurrent ischemic events, stent thrombosis or bleeding in clopidogrel treated patients. However, the association between TT homozygotes of the C3435T polymorphism and risk of short-term recurrent ischemic events may exist, but needs more studies to confirm.     

Differences in thrombus structure and kinetics in patients with type 2 diabetes mellitus after non ST elevation acute coronary syndrome

Introduction

Despite optimal secondary prevention therapy following non-ST elevation acute coronary syndrome (NSTE-ACS), recurrent thrombotic events are more frequent in patients with type 2 diabetes mellitus (T2DM).

Materials and Methods

This exploratory study was aimed to evaluate quantitative and qualitative aspects of thrombus. In 28 patients with and without T2DM treated with aspirin and clopidogrel we assessed thrombus quantity using an ex-vivo chamber, platelet reactivity, thrombus ultrastructure and thrombus kinetics one week after NSTE-ACS.

Results

T2DM was associated with increased thrombus [14861 (8003 to 30161) vs 8908 (6812 to 11996), μ²/mm, median (IQR), p = 0.045] and platelet reactivity. In addition, diabetic thrombus showed lower visco-elastic tensile strength [(− 0.2(− 1.7 to 0.7) vs 1.0(− 0.9 to 3.3), p = 0.044)] and was more resistant to autolysis [(27.8(11.7 to 70.7) vs 78.8(68.5 to109.6) mm/min, p = 0.002)]. On SEM, fibrin fibres in diabetes were thinner, with higher lateral interlinkage and mesh-like organisation. Thrombus quantity correlated inversely with thrombus retraction (r = − 0.450 p = 0.016) but not with platelet reactivity (r = 0.153, p = 0.544).

Conclusions

Despite optimal antiplatelet therapy, T2DM patients after NSTE-ACS developed increased thrombus of lower tensile strength and slower retraction. SEM revealed loosely arranged fibrin fibres. Our data showed significant differences in the magnitude as well as structural and mechanistic characteristics of thrombus in patients with T2DM.     

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.

Materiel and methods

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 600 mg 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 600 mg 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.     

Platelet activation increases in patients undergoing vascular surgery

Background

Platelets are a major contributor to atherothrombosis and may contribute to the heightened risk of perioperative cardiovascular events. We sought to examine changes in platelet activity in subjects undergoing vascular surgery.

Methods

Platelet activity in 18 patients (median age 74, 45% female) undergoing non-emergent open vascular surgery was assessed by light transmission aggregometry in response to saline, epinephrine and adenosine-5 diphosphate (ADP), and by flow cytometric analysis of monocyte-platelet aggregation (MPA). Platelet activity was assessed preoperatively (T1), 1-hour into the operation (T2), 1-hour (T3), 24-hours (T4) and 48-hours post-operatively (T5). Data were compared using the Wilcoxon Signed Ranks Test. Continuous variables are summarized as medians and (interquartile, IQR) ranges.

Results

Spontaneous platelet aggregation increased transiently during the surgical period (T1-5.8% [2.4, 10.8], T2-13.5% [9.3, 26.5], T3-7.5% [3.3, 17], T4-10.0% [7.3, 16.3], T5-7.25% [4.5, 29.9], P = 0.002). Similar trends in perioperative platelet activity were noted for platelet aggregation in response to epinephrine (P = 0.035) and ADP (P = 0.036). Using flow cytometry, we found an increase in MPA during the perioperative period (P = 0.047), which was most significant between T1 and T3 (P = 0.005).

Conclusions

Platelet activity increases significantly during and following open vascular surgery. This data may help explain the pathophysiology of increased thrombotic risk during the perioperative period of vascular surgery.     

CYP2C19*2 and other genetic variants affecting platelet response to clopidogrel in patients undergoing percutaneous coronary intervention

Introduction

Information regarding any possible additional effect of genetic variants other than CYP2C19*2 on platelet reactivity in patients undergoing percutaneous coronary intervention (PCI), while on dual antiplatelet therapy, is sparse.

Materials and Methods

Genotyping for CYP2C19*2, CYP2C19*17, CYP2C9*3, CYP2B6*5, ABCB1 and P2RY12 (c.-217 + 2739 T > C) variants was performed in 146 consecutive PCI patients receiving clopidogrel. Platelet reactivity was assessed by the Verify Now P2Y12 point-of-care assay and high on-treatment platelet reactivity (HTPR) was defined as a Platelet Reactivity Unit (PRU) ≥ 235.

Results

We identified 65(44.5%) patients with HTPR and 38(26%) carriers of at least one CYP2C19*2 allele, which had higher platelet reactivity compared to non-carriers [least square (LS) mean difference 44.5, 95%CI 15.8-77.3, p = 0.003]. In the entire study population, the presence of at least one CYP2C19*2 or P2RY12 allelic variant was independently associated with HTPR (OR = 3.02, 95%CI 1.16-7.86, p = 0.023 and OR = 3.11, 95%CI 1.03-9.39, p = 0.05 respectively). In CYP2C19*2 non-carriers, carriers of at least one CYP2B6*5 allelic variant had higher platelet reactivity compared to the remainders (LS mean difference 35.6, 95%CI 3.7-67.6, p = 0.03) and the presence of at least one CYP2B6*5 or P2RY12 allelic variant was independently associated with HTPR (OR = 3.26, 95%CI 1.08-9.86, p = 0.04 and OR = 4.27, 95%CI 1.11-16.4, p = 0.04 respectively).

Conclusions

Apart from the CYP2C19*2, other genetic variants involved in clopidogrel metabolism and action like CYP2B6*5 and P2RY12 seem to have an important association with HTPR.     

The influence of cytochrome oxidase CYP2A6, CYP2B6, and CYP2C9 polymorphisms on the plasma concentrations of valproic acid in epileptic patients

Objectives

To investigate influences of the functional polymorphisms of Cytochrome P450 isozymes 2A6 (CYP2A6), 2B6 (CYP2B6), and 2C9 (CYP2C9) on pharmacokinetics of VPA in vivo.

Patients and methods

In the study, we analyzed the genotypes of CYP2A6, CYP2B6, and CYP2C9 and their contribution to the steady-state standardized plasma VPA concentrations in 179 subjects with epilepsy of a Northern Han Chinese population. The genotypes were detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results

The subjects with one or two variant CYP2A6*4 alleles showed higher mean plasma VPA concentrations compared with non-*4 alleles [(3.4 ± 0.4) μg kg ml⁻¹ mg⁻¹ vs. (3.6 ± 0.4) μg kg ml⁻¹ mg⁻¹, p = 0.0055]. A significant difference [one-way ANOVA (p = 0.0203)] was also found between mean plasma VPA concentrations and the CYP2B6 genotypes. In addition, subjects with the heterozygous genotype CYP2C9*3 had higher mean plasma VPA concentrations than did those subjects with the wild-type genotype [(3.9 ± 0.4) μg kg ml⁻¹ mg⁻¹ vs. (3.4 ± 0.4) μg kg ml⁻¹ mg⁻¹, p = 0.0001].

Conclusion

The presently evaluated variant alleles in the CYP2A6, CYP2B6, and CYP2C9 genes may explain part of the substantial variability in VPA pharmacokinetics between different subjects.     

Suppression of angiogenic response in local vein wall is associated with reduced thrombus resolution

Introduction

The formation of new vascular channels within and around venous thrombus contributes to its resolution. Neovascularisation arising from the surrounding vein may facilitate this process. Treatment of cancer patients with anti-angiogenic agents can lead to increased incidence of venous thromboembolic events, but the effect of these agents on the processes that govern thrombus resolution are unclear. The aim of this study was to determine the effect of anti-angiogenic treatment with 2-methoxyestradiol (2ME) on (i) angiogenic response in the thrombosed vein and (ii) venous thrombus resolution.

Materials and methods

Venous thrombus was induced in the inferior vena cava (IVC) of 36 adult male BALB/C mice. Thrombosed mice received either the anti-angiogenic agent, 2ME (150 mg/kg/day, i/p), or vehicle control (n = 18/group). In the thrombosed IVC of both groups: hypoxia-inducible factor (HIF) 1α, and its angiogenic targets, vascular endothelial growth factor (VEGF) and placental growth factor (PLGF), were quantified using enzyme-linked immunosorbent assays at days 1 and 10 post-thrombus induction (n = 6/group); and inflammatory cell content, cell proliferation, and vein recanalisation were quantified using immunostaining and image analysis at day 10 (n = 6/group).

Results

In the IVC of mice treated with 2ME compared with control: HIF1α (P < 0.005 and P < 0.02), VEGF (P < 0.005 and P < 0.02), and PLGF levels (P < 0.01 and P < 0.001) were reduced at days 1 and 10 post-thrombus induction respectively, and macrophage content (P < 0.005), neutrophil content (P < 0.01), vein recanalistion (P < 0.05), and thrombus resolution (P < 0.001) were also reduced at day 10.

Conclusions

Anti-angiogenic treatment with 2ME supressed the HIF1-mediated angiogenic drive in local vein wall and attenuated venous thrombus resolution. The potential pro-thrombotic effect of anti-angiogenic agents should be carefully considered when managing venous thromboembolic events in cancer patients.     

Association between the plasminogen activator inhibitor-1 4G/5G polymorphism and risk of venous thromboembolism: A meta-analysis

Introduction

The plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism was considered to be associated with risk of venous thromboembolism (VTE), while evidence remains inadequate. To provide a more accurate estimation of this relationship, we performed an updated meta-analysis of all eligible studies.

Materials and Methods

A systematical search was performed in PubMed, EMBASE, Wanfang, China National Knowledge Infrastructure (CNKI) and Cqvip databases to identify relevant studies published before March 6^th 2014. The odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using the fixed/random-effects model using Review Manager 5.1 and STATA 12.0.

Results

A total of 34 studies with 3561 cases and 5693 controls were analyzed. Overall, significant association between the PAI-1 4G/5G variant and VTE risk in total population (dominant model: OR = 1.32, 95%CI: 1.13-1.54) was observed. And this variant was also related to the deep vein thrombosis risk (dominant model: OR = 1.60, 95%CI: 1.24-2.06, P = 0.0003). In the subgroup analyses on ethnicity, significant results were obtained in both Asians (dominant model: OR = 2.08, 95%CI: 1.29-3.35, P = 0.003) and Caucasians (dominant model: OR = 1.31, 95%CI: 1.10-1.56, P = 0.003). However, no significant association was found in patients with provoked VTE. In terms of subgroup analyses on co-existence of other thrombotic risk factors, the PAI-1 4G/5G polymorphism was significantly associated with VTE risk in patients with factor V Leiden mutation (dominant model: OR = 1.72, 95%CI: 1.17-2.53), but not in patients with cancer or surgery.

Conclusion

Our findings demonstrate the role of PAI-1 4G/5G polymorphism being a risk candidate locus for VTE susceptibility, especially in patients with other genetic thrombophilic disorders.     

Influence of CYP2C9 polymorphism and phenytoin co-administration on acenocoumarol dose in patients with cerebral venous thrombosis

Background

The study aimed at evaluating the contribution of genetic variations in the drug metabolizing enzyme, CYP2C9, and the influence of co-medication with the antiepileptic drug, phenytoin, to variability in acenocoumarol response, in patients with cerebral venous thrombosis (CVT).

Methods

476 acenocoumarol-treated CVT patients (153 males and 323 females) were genotyped for CYP2C9*2 and CYP2C9*3 polymorphisms by PCR-RFLP method. Mean acenocoumarol dose required for achieving and maintaining a stable international normalized ratio (INR) was calculated for different genotypes. The effect of co-administration with phenytoin was determined.

Results

Genotype distributions of CYP2C9 were as follows: 83%CYP2C9*1/*1, 8.6%CYP2C9*1/*3, 5.9%CYP2C9*1/*2, 1.9%CYP2C9*3/*3, 0.4%CYP2C9*2/*3 and 0.2%CYP2C9*2/*2. During the initiation phase of anticoagulation the CYP2C9*2 allele was independently associated with low acenocoumarol dose requirement (Adjusted OR 5.38; 95%CI 1.65-17.49; p = 0.005). Similarly, the adjusted odds ratio for requiring a low dose during the induction phase in patients bearing the CYP2C9*3 allele was 12.79 (95%CI 4.74-34.57; p < 0.0001). During the maintenance phase, CYP2C9*2 and CYP2C9*3 alleles were associated with 19-fold (Adjusted OR 19.67; 95%CI 2.46-157.19; p = 0.005) and 11.9-fold odds (Adjusted OR 11.98; 95%CI 2.61-55.08; p = 0.001) of requiring a low dose. Clinical covariates such as age, alcohol consumption, postpartum state and oral contraceptive intake also influenced acenocoumarol dosage. Co-medication with phenytoin was associated with lower dose requirement across genotypes during the initiation phase. However, during the maintenance phase, phenytoin-treated patients of all genotypes required higher doses of acenocoumarol.

Conclusion

This study emphasizes the fact that polymorphisms in CYP2C9 gene and co-medication with phenytoin alter the anticoagulant effect of acenocoumarol.     

Paraoxonase-1 activity affects the clopidogrel response in CYP2C19 loss-of-function carriers

Background

The impact of paraoxonase-1 (PON1) activity on the response to clopidogrel may differ in patients treated with drug-eluting stents (DES) in association with CYP2C19 loss-of-function (LOF) polymorphisms.

Methods

This study included 112 Japanese patients receiving clopidogrel (75 mg/day) and aspirin (100 mg/day) who underwent optical coherence tomography (OCT) examination 9 months after DES implantation. The CYP2C19 genotype was analyzed and LOF carriers (*1/*2, *1/*3, *2/*2, *3/*3, *2/*3) were identified. At the 9-month follow-up, platelet reactivity was determined by measuring the P2Y12 reactivity unit (PRU) using a VerifyNow P2Y12 assay, PON1 activity was evaluated and intra-stent thrombus was evaluated by OCT.

Results

Of the 112 Japanese patients, 75 were LOF carriers (67.0%). The patients were divided into tertiles according to the PON1 activity (tertile 1; < 230 U/L, tertile 2; 230–283 U/L, tertile 3; > 283 U/L). In the VerifyNowP2Y12 analysis, tertile 1 had a higher PRU than tertiles 2 and 3 in LOF carriers, and there was no difference among tertiles in non-carriers. The highest incidence of intra-stent thrombus was observed in tertile 1 followed by tertiles 2 and 3 in LOF carriers, whereas there was no such difference in non-carriers. Multivariate analysis revealed that LOF carriers and PON1 activity tertile 1 were independent predictors of intra-stent thrombus in all patients. In LOF carriers, tertile 1 was the only independent predictor for intra-stent thrombus.

Conclusion

Low PON1 activity is associated with a low response to clopidogrel and a high frequency of intra-stent thrombus only in LOF carriers.     

Menstrual mood disorders are associated with blunted sympathetic reactivity to stress

Objective

Few studies have directly compared women with a menstrually related mood disorder (MRMD) with women who have suffered from depression for stress reactivity phenotypes. It is unclear whether blunted responses to stress in women with a MRMD reflect a unique phenotype of MRMDs or may be explained by a history of depression.

Methods

We assessed cardiovascular reactivity to stress in four groups: 1) Women with a MRMD without a history of depression (n = 37); 2) women with a MRMD plus a history of depression (n = 26); 3) women without a MRMD and without a history of depression (n = 43); and 4) women without a MRMD but with a history of depression (n = 20).

Results

Women with a MRMD showed blunted myocardial (heart rate and cardiac index) reactivity to mental stress compared to non-MRMD women, irrespective of histories of depression. Hypo-reactivity to stress predicted greater premenstrual symptom severity in the entire sample. Women with a MRMD showed blunted norepinephrine and diastolic blood pressure stress reactivity relative to women with no MRMD, but only when no history of depression was present. Both MRMD women and women with depression histories reported greater negative subjective responses to stress relative to their non-MRMD and never depressed counterparts.

Conclusion

Our findings support the assertion that a blunted stress reactivity profile represents a unique phenotype of MRMDs and also underscore the importance of psychiatric histories to stress reactivity. Furthermore, our results emphasize the clinical relevance of myocardial hypo-reactivity to stress, since it predicts heightened premenstrual symptom severity.     

Endothelial nitric oxide synthase 894 G > T polymorphism and thrombotic disease: A Meta-Analysis of 17 studies involving 8808 subjects

Introduction

Endothelial nitric oxide synthase (eNOS) 894 G > T polymorphism may influence the risk of thrombotic disease, but data from published studies with low statistical power are inconclusive. To investigate the association between the gene polymorphism and thrombotic disease, a meta-analysis was performed.

Materials and Methods

Case–control studies evaluating the association between the eNOS G894T polymorphism, Glu298Asp and thrombotic disease were searched in PubMed, OVID, Web of Science, Google Scholar and China Biology Medicine disc (CBM). Data were available for 4742 cases and 4066 controls from 17 studies.

Results

In all, although there was a significant association between G894T and thrombotic disease (G/T + T/T vs. G/G: OR = 1.364, 95%CI = 1.126-1.652, P = 0.001; T/T vs. G/T + G/G: OR = 1.861, 95%CI = 1.207-2.870, P = 0.005; TT vs. GG: OR = 1.938, 95%CI = 1.244-3.021, P = 0.003; G/T vs. G/G: OR = 1.225, 95%CI = 1.022-1.469, P = 0.028), there was significant heterogeneity among studies (P* < 0.001). In subgroup analysis, there was significant association with no heterogeneity in venous thrombosis (G/T + T/T vs. G/G: OR = 1.409, 95%CI = 1.135-1.750, P = 0.002, P* = 0.508; T/T vs. G/G: OR = 1.640, 95%CI = 1.011-2.660, P = 0.045, P* = 0.333; G/T vs. G/G: OR = 1.357, 95%CI = 1.082-1.701, P = 0.008, P* = 0.595) and in Asian population (G/T + T/T vs. G/G: OR = 1.722, 95%CI = 1.443-2.055, P < 0.001, P* = 0.541; T/T vs. G/T + G/G: OR = 2.357, 95%CI = 1.389-4.000, P = 0.001, P* = 0.908; T/T vs. G/G: OR = 2.813, 95%CI = 1.645-4.810, P < 0.001, P* = 0.969; G/T vs. G/G: OR = 1.645, 95%CI = 1.370-1.975, P < 0.001, P* = 0.489).

Conclusions

Findings of this meta-analysis demonstrated that eNOS G894T polymorphism may be a risk factor for venous thrombosis, and in Asia the polymorphism may increase the risk of developing thrombotic disease.