Roles of miR-223 in Platelet Function and High On-Treatment Platelet Reactivity: A Brief Report and Review

BACKGROUND

Platelets are highly enriched in microRNAs (miRNAs), which are genomically encoded 19-25 nucleotide non-coding RNAs that target complementary mRNAs through total or near-total base pairing. MiR-223 is among the most abundant miRNAs in human and murine platelets, but despite ongoing investigations in recent years, miR-223 roles in platelet physiology and its putative roles in high on-treatment platelet reactivity (HTPR) remain controversial, as studies showed varying findings.

OBJECTIVES

In the current hybrid review/report, we aim to compare studies that investigated miR-223 in platelet function and HTPR. Additionally, we briefly report our own findings on murine miR-223-deficient platelets.

METHODS

We have thoroughly searched the literature and found three studies that investigated the roles of miR-223 in platelet function by utilizing miR-223 global knockout mice, and three studies that explored the association between miR-223 and residual platelet reactivity by measuring miR-223 levels in platelets of patients treated with clopidogrel for cardiac artery disease. We assessed platelet function in response to different agonists and evaluated P2y12 levels in male and female miR-223-deficient platelets.

RESULTS

Integrin activation and α granule secretion were similar between WT and KO platelets in response to all agonists in platelets from both female and male mice, although both genotypes showed elevated thrombin response in females compared to males.

CONCLUSIONS

In all studies, including ours, taken together, miR-233 appears to play a modest role in platelet function and development of HTPR.

Influence of GAS5/MicroRNA-223-3p/P2Y12 Axis on Clopidogrel Response in Coronary Artery Disease

Background Dual antiplatelet therapy based on aspirin and P2Y12 receptor antagonists such as clopidogrel is currently the primary treatment for coronary artery disease (CAD). However, a percentage of patients exhibit clopidogrel resistance, in which genetic factors play vital roles. This study aimed to investigate the roles of GAS5 (growth arrest-specific 5) and its rs55829688 polymorphism in clopidogrel response in patients with CAD. Methods and Results A total of 444 patients with CAD receiving dual antiplatelet therapy from 2017 to 2018 were enrolled to evaluate the effect of GAS5 single nucleotide polymorphism rs55829688 on platelet reactivity index. Platelets from 37 patients of these patients were purified with microbeads to detect GAS5 and microRNA-223-3p (miR-223-3p) expression. Platelet-rich plasma was isolated from another 17 healthy volunteers and 46 newly diagnosed patients with CAD to detect GAS5 and miR-223-3p expression. A dual-luciferase reporter assay was performed to explore the interaction between miR-223-3p and GAS5 or P2Y12 3'-UTR in (human embryonic kidney 293 cell line that expresses a mutant version of the SV40 large T antigen) HEK 293T and (megakaryoblastic cell line derived in 1983 from the bone marrow of a chronic myeloid leukemia patient with megakaryoblastic crisis) MEG-01 cells. Loss-of-function and gain-of-function experiments were performed to reveal the regulation of GAS5 toward P2Y12 via miR-223-3p in MEG-01 cells. We observed that rs55829688 CC homozygotes showed significantly decreased platelet reactivity index than TT homozygotes in CYP2C19 poor metabolizers. Platelet GAS5 expression correlated positively with both platelet reactivity index and P2Y12 mRNA expressions, whereas platelet miR-223-3p expression negatively correlated with platelet reactivity index. Meanwhile, a negative correlation between GAS5 and miR-223-3p expressions was observed in platelets. MiR-223-3p mimic reduced while the miR-223-3p inhibitor increased the expression of GAS5 and P2Y12 in MEG-01 cells. Knockdown of GAS5 by siRNA increased miR-223-3p expression and decreased P2Y12 expression, which could be reversed by the miR-223-3p inhibitor. Meanwhile, overexpression of GAS5 reduced miR-223-3p expression and increased P2Y12 expression, which could be reversed by miR-223-3p mimic. Conclusions GAS5 rs55829688 polymorphism might affect clopidogrel response in patients with CAD with the CYP2C19 poor metabolizer genotypes, and GAS5 regulates P2Y12 expression and clopidogrel response by acting as a competitive endogenous RNA for miR-223-3p.

Association of FMO3 rs1736557 polymorphism with clopidogrel response in Chinese patients with coronary artery disease

PURPOSE

Dual antiplatelet therapy with aspirin and clopidogrel is commonly used for coronary artery disease (CAD) patients undergoing percutaneous coronary intervention to prevent stent thrombosis and ischemic events. However, some patients show high on-treatment platelet reactivity (HTPR) during clopidogrel therapy. Genetic factors such as loss-of-function variants of CYP2C19 are validated to increase the risk of HTPR. Flavin-containing monooxygenase 3 (FMO3) is reported to be associated with potency of platelet responsiveness and thrombosis. This study aimed to explore the association between FMO3 rs1736557 polymorphism and clopidogrel response.

METHODS

Five hundred twenty-two Chinese CAD patients treated with dual antiplatelet therapy were recruited from Xiangya Hospital. After oral administration of 300 mg loading dose (LD) clopidogrel for 12-24 h or 75 mg daily maintenance dose (MD) clopidogrel for at least 5 days, the platelet reaction index (PRI) was determined by vasodilator-stimulated phosphoprotein-phosphorylation assay. FMO3 rs1736557, CYP2C19*2, and CYP2C19*3 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Mean PRI value was significantly higher in CYP2C19 poor metabolizers (PMs) and intermediate metabolizers (IMs) than the extensive metabolizers (EMs) (p < 0.001). In addition, FMO3 rs1736557 AA homozygotes showed significantly lower PRI as compared with carriers of the major rs1736557 G allele in the entire cohort and in the MD cohort (p = 0.011, p = 0.008, respectively). The risk of HTPR was decreased significantly in carriers of the rs1736557 A allele (AA vs GG: OR = 0.316, 95% CI: 0.137-0.726, p = 0.005; AA vs GA: OR = 0.249, 95% CI: 0.104-0.597, p = 0.001; AA vs GG+GA: OR = 0.294, 95% CI: 0.129-0.669, p = 0.002), and the association was observed mainly in patients carrying the CYP2C19 LOF allele and in those administered with MD.

CONCLUSION

The FMO3 rs1736557 AA genotype was related to an increased the antiplatelet potency of clopidogrel in Chinese CAD patients. Additional studies are required to verify this finding.

Tailored Adjunctive Cilostazol Therapy Based on CYP2C19 Genotyping in Patients With Acute Myocardial Infarction - The CALDERA-GENE Study

BACKGROUND

Patients with reduced-function CYP2C19 genotypes on dual antiplatelet therapy (DAPT) with aspirin and clopidogrel show higher clinical risk for acute myocardial infarction (AMI). We investigated the effect of CYP2C19 genotype-tailored adjunctive cilostazol therapy on treatment of AMI.

METHODS AND RESULTS

The study group of 138 patients with suspected AMI were screened for CYP2C19 genotype immediately after percutaneous coronary intervention (PCI) using a SPARTAN RX point-of-care device. Carriers of the CYP2C19 reduced-function allele were randomized into DAPT (Carrier/DAPT) and DAPT plus 14-day cilostazol (Carrier/DAPT+Cilostazol) groups, while noncarriers were treated with DAPT (Noncarrier/DAPT). After exclusion of 10 patients, the remaining 128 patients were analyzed for P2Y12 reaction unit (PRU) using VerifyNow®P2Y12 system, and levels of biomarkers immediately after, and 1, 14, and 28 days after PCI. DAPT+Cilostazol reduced PRU levels in carriers (n=46) to those found in the Noncarrier/DAPT group (n=40), and significantly lower than those of the Carrier/DAPT group (n=42) at 14 days post-PCI. Discontinuation of cilostazol for 14 days was associated with a significant rise in PRU levels to those of the Carrier/DAPT group at 28 days post-PCI. Plasma B-type natriuretic peptide levels at 14 days post-PCI were lower in Carrier/DAPT+Cilostazol than in the other 2 groups, and the levels increased to those of the other groups at 28 days post-PCI after withdrawal of cilostazol.

CONCLUSIONS

Adjunctive cilostazol therapy tailored to CYP2C19 genotype seemed useful in AMI patients with the CYP2C19 reduced-function allele.

Total Thrombus-formation Analysis System Predicts Periprocedural Bleeding Events in Patients With Coronary Artery Disease Undergoing Percutaneous Coronary Intervention

BACKGROUND

Periprocedural bleeding events are common after percutaneous coronary intervention. We evaluated the association of periprocedural bleeding events with thrombogenicity, which was measured quantitatively by the Total Thrombus-formation Analysis System equipped with microchips and thrombogenic surfaces (collagen, platelet chip [PL]; collagen plus tissue factor, atheroma chip [AR]).

METHODS AND RESULTS

Between August 2013 and March 2016, 313 consecutive patients with coronary artery disease undergoing elective percutaneous coronary intervention were enrolled. They were divided into those with or without periprocedural bleeding events. We determined the bleeding events as composites of major bleeding events defined by the International Society on Thrombosis and Hemostasis and minor bleeding events (eg, minor hematoma, arteriovenous shunt and pseudoaneurysm). Blood samples obtained at percutaneous coronary intervention were analyzed for thrombus formation area under the curve (PL₂₄-AUC₁₀ for PL chip; AR₁₀-AUC₃₀ for AR chip) by the Total Thrombus-formation Analysis System and P2Y12 reaction unit by the VerifyNow system. Periprocedural bleeding events occurred in 37 patients. PL₂₄-AUC₁₀ levels were significantly lower in patients with such events than those without (P=0.002). Multiple logistic regression analyses showed association between low PL₂₄-AUC₁₀ levels and periprocedural bleeding events (odds ratio, 2.71 [1.22-5.99]; P=0.01) and association between PL₂₄-AUC₁₀ and periprocedural bleeding events in 176 patients of the femoral approach group (odds ratio, 2.88 [1.11-7.49]; P=0.03). However, PL₂₄-AUC₁₀ levels in 127 patients of the radial approach group were not significantly different in patients with or without periprocedural bleeding events.

CONCLUSIONS

PL₂₄-AUC₁₀ measured by the Total Thrombus-formation Analysis System is a potentially useful predictor of periprocedural bleeding events in coronary artery disease patients undergoing elective percutaneous coronary intervention.

Does percutaneous coronary stent implantation increase platelet reactivity?

High platelet reactivity (PR) values on treatment with clopidogrel are associated with an increased rate of thrombotic events after a percutaneous coronary intervention (PCI). However, we do not know the optimal timing of the performance of the PR measurements. Platelets might be activated during a PCI, which means that the timing of PR measurements, before or after PCI, could influence the outcome. In turn, this could lead to misinterpretation of the patient's response to antiplatelet therapy and a less accurate prediction of the patient's risk of thrombotic events during follow-up. We aimed to evaluate the effect of stent implantation on PR in patients with and without acute coronary syndromes who undergo PCI to assess the optimal timing of PR measurements. A systematic literature search was performed and the results are summarized in this review.

Impact of preoperative dual antiplatelet therapy on bleeding complications in patients with acute coronary syndromes who undergo urgent coronary artery bypass grafting

BACKGROUND

A 5- to 7-day washout period before coronary artery bypass grafting (CABG) is recommended for patients who have recently received a thienopyridine derivative; however, data supporting this guideline recommendation are lacking in Japanese patients.

METHODS

Urgent isolated CABG was performed in 130 consecutive patients with acute coronary syndromes (ACS) (101 men; mean age, 69 years). Urgent CABG was defined as operation performed within 5 days after coronary angiography. All patients continued to receive aspirin 100mg/day. The subjects were retrospectively divided into 2 groups: 30 patients with preoperative thienopyridine (clopidogrel in 15 patients, ticlopidine in 15) exposure within 5 days [dual antiplatelet therapy (DAPT) group] and 100 patients without exposure [single antiplatelet therapy (SAPT) group].

RESULTS

Although the DAPT group had a higher proportion of patients who received perioperative platelet transfusions than the SAPT group (50% vs. 18%, p<0.001), intraoperative bleeding (median, 1100ml; interquartile range, 620-1440 vs. 920ml; 500-1100) and total drain output within 48h after surgery (577±262 vs. 543±277ml) were similar. CABG-related major bleeding, which was defined as type 4 or 5 bleeding according to the Bleeding Academic Research Consortium definitions, occurred in a significantly higher proportion of patients in the DAPT group than in the SAPT group (20% vs. 3%, p=0.005). This difference in major bleeding was driven mainly by the higher rate of transfusion of ≥5U red blood cells within a 48-h period in the DAPT group (13% vs. 1%, p=0.01). There was no significant difference in the 30-day composite endpoint including death, myocardial (re)infarction, ischemic stroke, and refractory angina between the DAPT group and SAPT group (17% vs. 19%).

CONCLUSIONS

Preoperative DAPT increases the risk of CABG-related major bleeding in Japanese patients with ACS undergoing urgent CABG.

CYP Genetic Variants, CYP Metabolite Levels, and Symptomatic Carotid Stenosis in Ischemic Stroke Patients

AIM

To evaluate the relationship between CYP genetic polymorphisms and CYP metabolite levels with carotid artery stenosis in acute ischemic stroke (IS) patients.

METHODS

Eleven single nucleotide polymorphisms (SNPs) of seven CYP genes were genotyped in 136 IS patients with carotid stenosis and 158 patients without carotid stenosis. CYP plasma metabolite levels [20-hydroxyeicosatetraenoic acid (HETE), total epoxyeicosatrienoic acids (EETs), and dihydroxyeicosatrienoic acids (DiHETEs)] were assessed in a subsample of 90 patients with carotid stenosis and 96 patients without carotid stenosis. We evaluated the relationship between assessed variants and carotid stenosis risk, variants with CYP metabolite levels, and variants in mediating the differences of CYP metabolite levels between patients with carotid stenosis and those without. Additionally, gene-gene interactions were analyzed to assess the interactive role of the assessed variants in affecting CYP metabolite levels and risk of carotid stenosis.

RESULTS

The genotypes of rs17110453CC, rs751141GG, and rs9333025GG were significantly associated with carotid stenosis risk. Also these polymorphisms were associated with CYP plasma metabolite levels in patients with carotid stenosis. There was a significant gene-gene interaction between rs17110453 and rs9333025 in affecting the risk of carotid stenosis. Patients with rs17110453CC and rs9333025GG had a significantly higher risk of carotid stenosis than those with 17110453AA and rs9333025AA (OR=2.12, 95% CI: 1.13-7.26, P=0.013).

CONCLUSIONS

Specific CYP450 gene SNPs and their interactions are associated with CYP450 plasma metabolite levels, which may partially explain their associations with carotid stenosis. Further studies are needed to validate our findings.

Comparison between the Outcomes of Intracoronary and Intravenous Administration of Eptifibatide during Primary Percutaneous Coronary Intervention in Patients with Acute ST-Elevation Myocardial Infarction

AIM

To compare the outcomes of intracoronary (IC) and intravenous (IV) administration of eptifibatide during primary percutaneous coronary intervention (PPCI) in patients with ST-elevation myocardial infarction (STEMI).

METHODS

In this prospective double-blind randomized clinical trial, 76 patients with STEMI selected for PPCI were randomly assigned in two groups to receive either IC or IV bolus of eptifibatide. The primary end point was coronary perfusion assessment by thrombolysis in myocardial infarction (TIMI) flow grade (TFG), TIMI perfusion grade (TPG), and corrected TIMI frame count (cTFC). Secondary end points were left ventricular ejection fraction (LVEF) restoration, ST-segment elevation resolution, and in-hospital major cardiovascular adverse events (MACEs) (including recurrent MI, need for target vessel revascularization (TVR), stroke, and death resulting from any cause) until discharge.

RESULTS

Assessment revealed significantly better TFG (95% CI: 1.01-10.26, OR=3.224, P=0.042), more TFG 3 (65.79% vs. 86.11% in IV and IC groups, respectively), better TPG (P=0.024), more achieved TPG 3 and TPG 2＋3 (TPG 3: 44.74% vs. 72.22% and TPG 2＋3: 78.95% vs. 94.44% in the IV and IC groups, respectively) with better cTFC in the IC group (37.33±15.84 vs. 32.53± 20.71 in the IV and IC groups, respectively; P=0.034). LVEF was better restored in the IC group (6.21±8.61% vs. 14.72±5.34% in the IV and IC groups, respectively; P＜0.001) and the ST-segment elevation resolution was better achieved in the IC administration (95% CI: -22.55 to -6.23, P=0.001). There were no recurrent MI, stroke, or need for TVR among patients during the in-hospital stay.

CONCLUSIONS

IC administration of eptifibatide during PPCI in patients with STEMI in comparison with IV administration of eptifibatide is associated with significantly better coronary reperfusion and improved clinical outcomes (IRCT2012090510751N1).

Effects of CYP2C19 and P2Y12 Gene Polymorphisms on Clinical Results of Patients Using Clopidogrel after Acute Ischemic Cerebrovascular Disease

The CY2C19 and P2Y12 gene polymorphisms are responsible for resistance to clopidogrel, known as drug unresponsiveness. In this study we researched the effect of gene polymorphism on clinical results of patients who began clopidogrel therapy after acute ischemic cerebrovascular disease.

The study included 51 patients. The patient group included patients who had begun prophylactic clopidogrel due to acute ischemic cerebrovascular disease in the last 2 years. All patients were monitored by the Neurology Outpatient Clinic at Çanakkale Onsekiz Mart Üniversity Research Hospital, Çanakkale, Turkey, and only those monitored for at least 1 year were included in the study.

When the *1, *2 and *3 alleles of the CYP2C19 gene polymorphism were evaluated, two patients were homozygotes for *2/*2, 13 patients were heterozygous for *1/*2 and 36 patients were homozygotes for the wild type *1/*1. No patient had the *3 allele. Three heterozygous patients, one for *2/*2 and two for *1/*2, stopped clopidogrel therapy due to repeated strokes and began taking warfarin. When evaluating P2Y12 52 (G>T) and 34 (C>T) polymorphisms, all alleles were of the wild type.

The CYP2C19 and P2Y12 gene polymorphisms may cause recurring strokes linked to insufficient response to treatment of ischemic cerebrovascular disease. In our patient group, three patients suffered repeated strokes and these patients had the CYP2C19*2 gene polymorphism. As a result, before medication use, genetic testing is important for human life, quality of life and economic burden.

Contemporary antiplatelet therapy in patients undergoing percutaneous coronary intervention

The proper use of antiplatelet agents in the cardiac catheterization laboratory is important for ensuring optimal results in patients undergoing percutaneous revascularization. Understanding the mechanisms by which these drugs exerts their effects is important for both interventional and non-interventional cardiologists. The effects of these agents on platelet function can be assessed and monitored using a variety of commercially available laboratory assays but so far these tests have not been adopted in routine clinical practice. Currently, aspirin, thienopyridines and glycoprotein IIb/IIIa inhibitors are the primary types of antiplatelet drugs being utilized. The use of these drugs and of several newer antiplatelet drugs in the treatment of patients undergoing percutaneous revascularization in the cardiac catheterization laboratory will be discussed, especially in the light of the recently published guidelines.