Comparison of the influence of ticagrelor and clopidogrel on inflammatory biomarkers and vascular endothelial function for patients with ST-segment elevation myocardial infarction receiving emergency percutaneous coronary intervention: study protocol for a randomized controlled trial

IL10 promoter variants are associated with gene expression but they are not markers of susceptibility to acute coronary syndrome

Interleukin-10 (IL-10) is an immunomodulatory cytokine that plays a pivotal role in the pathogenesis of acute coronary syndromes (ACS). Here, we evaluated the role of IL10 promoter variants as markers for ACS susceptibility in Western Mexican patients as well as its association with IL10 mRNA and IL-10 plasma levels. Three promoter variants (- 1082 A > G, - 819 T > C and - 592 A > C) were analyzed in 300 ACS patients and 300 control group (CG) individuals. IL10 relative gene expression was evaluated in peripheral blood mononuclear cells (PBMC) and IL-10 levels were quantified in plasma. The allelic, genotypic and haplotypic frequencies did not show significant differences between groups. ACS patients had sevenfold higher mRNA IL10 level compared to CG (p = 0.0013). Homozygous C/C carriers in both - 819 T > C and - 592 A > C variants had 0.4-fold higher IL10 mRNA expression than heterozygous and polymorphic allele homozygous genotypes (p = 0.0357) in ACS group. There were significant differences in plasma IL-10 levels in CG and ACS group (1.001 vs 1.777 pg/mL, p = 0.0051). The variants were not markers of susceptibility to ACS in Western Mexican individuals. ACS patients showed higher IL10 expression than CG individuals which could be mediated by - 819 T > C and - 592 A > C variants and pharmacotherapy.

The role of Vav3 expression for inflammation and cell death during experimental myocardial infarction

OBJECTIVES

Myocardial Infarction (MI) is the leading cause of chronic heart failure. Previous studies have suggested that Vav3, a receptor protein tyrosine kinase signal transducer, is associated with a variety of cellular signaling processes such as cell morphology regulation and cell transformation with oncogenic activity. However, the mechanism of Vav3-mediated MI development requires further investigation.

METHOD

Here, The authors established an MI rat model by ligating the anterior descending branch of the left coronary artery, and an MI cell model by treating cardiomyocytes with H2O2. Microarray analysis was conducted to identify genes with differential expression in heart tissues relevant to MI occurrence and development. Vav3 was thus selected for further investigation.

RESULTS

Vav3 downregulation was observed in MI heart tissue and H2O2-treated cardiomyocytes. Administration of Lentiviral Vav3 (LV-VAV3) in MI rats upregulated Vav3 expression in MI heart tissue. Restoration of Vav3 expression reduced infarct area and ameliorated cardiac function in MI rats. Cardiac inflammation, apoptosis, and upregulation of NFκB signal in heart tissue of MI animals were assessed using ELISA, TUNEL staining, real-time PCR, and WB. Vav3 overexpression reduced cardiac inflammation and apoptosis and inhibited NFκB expression and activation. Betulinic Acid (BA) was then used to re-activate NFκB in Vav3-overexpressed and H2O2-induced cardiomyocytes. The expression of P50 and P65, as well as nuclear P65, was significantly increased by BA exposure.

CONCLUSIONS

Vav3 might serve as a target to reduce ischemia damage by suppressing the inflammation and apoptosis of cardiomyocytes.

The Effect of Platelet-Rich Plasma on Endothelial Progenitor Cell Functionality

Platelets mediate circulating endothelial progenitor cell (EPC) recruitment and maturation, participating in vascular repair, however the underlying mechanism(s) remain unclear. We investigated the effect of platelet-rich plasma (PRP) on the functionality of CD34+-derived late-outgrowth endothelial cells (OECs) in culture. Confluent OECs were coincubated with PRP under platelet aggregation (with adenosine diphosphate; ADP) and nonaggregation conditions, in the presence/absence of the reversible P2Y12 platelet receptor antagonist ticagrelor. Outgrowth endothelial cell activation was evaluated by determining prostacyclin (PGI2) and monocyte chemoattractant protein-1 (MCP-1) release and intercellular adhesion molecule-1 (ICAM-1) membrane expression. Similar experiments were performed using human umbilical vein endothelial cells (HUVECs). Platelet-rich plasma increased ICAM-1 expression and PGI2 and MCP-1 secretion compared with autologous platelet-poor plasma, whereas ADP-aggregated platelets in PRP did not exhibit any effect. Platelet-rich plasma pretreated with ticagrelor prior to activation with ADP increased all markers to a similar extent as PRP. Similar results were obtained using HUVECs. In conclusion, PRP induces OEC activation, a phenomenon not observed when platelets are aggregated with ADP. Platelet inhibition with ticagrelor restores the PRP capability to activate OECs. Since EPC activation is important for endothelial regeneration and angiogenesis, we suggest that agents inhibiting platelet aggregation, such as ticagrelor, may promote platelet-EPC interaction and EPC function.

No Differences in Levels of Circulating Progenitor Endothelial Cells or Circulating Endothelial Cells Among Patients Treated With Ticagrelor Compared With Clopidogrel During Non- ST -Segment-Elevation Myocardial Infarction

Background

Ticagrelor use during acute coronary syndromes demonstrated a decrease in all‐cause mortality in the PLATO (Platelet Inhibition and Patient Outcomes) trial. This effect has been attributed to a non–platelet‐derived improvement in endothelial function. The aim of this study was to determine differences in the number of endothelial progenitor cells and/or circulating endothelial cells found in peripheral blood in patients treated with either ticagrelor or clopidogrel during non–ST‐segment–elevation myocardial infarction.

Methods and Results

In this multicenter, randomized study (NCT02244710), patients were considered for inclusion after non–ST‐segment–elevation myocardial infarction whenever they were P2Y₁₂‐inhibitor naïve. Ticagrelor and clopidogrel were allocated at a 1:1 ratio. Blood samples for determining endothelial progenitor cells and circulating endothelial cells were extracted before the antiplatelet loading dose, 48 hours after presentation of index symptoms, and 1 month after the event. A multichannel cytometer was used for optimal cell characterization. A total of 96 patients fulfilled the inclusion criteria. Circulating endothelial cell levels corrected by white blood cells were as follows at baseline, 48 hours, and 1 month: 44 (28–64), 50 (33–63), and 38 (23–62) cells/mL, respectively, for clopidogrel and 38 (29–60), 45 (32–85), and 35 (24–71) cells/mL, respectively, for ticagrelor (P=0.6). Endothelial progenitor cell levels were 29 (15–47), 27 (15–33), and 18 (10–25) cells/mL, respectively, for clopidogrel and 20 (11–33), 22 (12–32), and 18 (11–29) cells/mL, respectively, for ticagrelor (P=0.9). No differences in intraindividual changes were found.

Conclusions

Patients treated with ticagrelor during non–ST‐segment–elevation myocardial infarction, in comparison to clopidogrel, showed similar levels of endothelial progenitor cells and circulating endothelial cells. These data suggest that the endothelial protective effect mediated by ticagrelor is not related to bone marrow physiology modulation.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02244710.

The Utility of Anti-Inflammatory Agents in Cardiovascular Disease: A Novel Perspective on the Treatment of Atherosclerosis

Approximately 40% of heart attack survivors remain at increased risk of recurrent cardiovascular events, despite the current treatment options showing that atherothrombosis is not exclusively a disorder of lipoprotein aggregation in the arterial wall. Clinical and experimental data suggest that inflammation plays an important role in atherothrombosis independent of the cholesterol level. Acute-phase reactants, such as C-reactive protein, increase in patients with coronary artery disease and are known to predict adverse outcomes in such patients. The recent CANTOS trial published in The New England Journal of Medicine provides evidence that interleukin-1β along with other cytokines play central roles in the inflammatory reaction that drives the interleukin-6 signaling pathway and have profound effects on cardiovascular outcomes. Several other ongoing studies are focused on multiple immune mediators involved in this process to support the inflammatory hypothesis of cardiovascular diseases. These new classes of drugs could represent the biggest breakthrough in cardiovascular medicine, which could have the greatest impact on cardiovascular mortality since the advent of statins. The drug canakinumab has shown promise in lowering atherosclerosis, and other drugs, such as colchicine and methotrexate, are gaining interest and are being investigated in multiple ongoing trials. A major concern is the affordability of these drugs, as most cardiovascular diseases are noted among people of lower socioeconomic statuses. The LoDoCo trial showed some benefits of colchicine, and whether this old drug can be marketed with a new label for cardiovascular disease remains in question. Therefore, a clear understanding of the different inflammatory pathways involved in atherosclerosis is needed to help develop more effective treatment modalities that will benefit humankind.

Ticagrelor Improves Endothelial Function by Decreasing Circulating Epidermal Growth Factor (EGF)

Ticagrelor is one of the most powerful P2Y₁₂ inhibitor. We have recently reported that, in patients with concomitant Stable Coronary Artery Disease (SCAD) and Chronic Obstructive Pulmonary Disease (COPD) undergoing percutaneous coronary intervention (PCI), treatment with ticagrelor, as compared to clopidogrel, is associated with an improvement of the endothelial function (Clinical Trial NCT02519608). In the present study, we showed that, in the same population, after 1 month treatment with ticagrelor, but not with clopidogrel, there is a decrease of the circulating levels of epidermal growth factor (EGF) and that these changes in circulating levels of EGF correlate with on-treatment platelet reactivity. Furthermore, in human umbilical vein endothelial cells (HUVEC) incubated with sera of the patients treated with ticagrelor, but not with clopidogrel there is an increase of p-eNOS levels. Finally, analyzing the changes in EGF and p-eNOS levels after treatment, we observed an inverse correlation between p-eNOS and EGF changes only in the ticagrelor group. Causality between EGF and eNOS activation was assessed in vitro in HUVEC where we showed that EGF decreases eNOS activity in a dose dependent manner. Taken together our data indicate that ticagrelor improves endothelial function by lowering circulating EGF that results in the activation of eNOS in the vascular endothelium.

Isoquercetin ameliorates myocardial infarction through anti-inflammation and anti-apoptosis factor and regulating TLR4-NF-κB signal pathway

The aim of the present study was to investigate the protective mechanisms and identify the effects of isoquercetin on myocardial infarction in a rat model of acute myocardial infarction (AMI). Isoquercetin ameliorated myocardial infarct size, creatine kinase (CK), CK‑MB and lactic dehydrogenase activity and inhibited inflammation, oxidative stress and heart cell apoptosis in a rat with AMI. Isoquercetin increased endothelial nitric oxide synthase, reduced inducible nitric oxide synthase levels and suppressed the Toll-like receptor 4‑nuclear factor (TLR4‑NF)‑κB signaling pathway in a rat with AMI. Overall, isoquercetin ameliorated AMI through anti‑inflammatory and anti‑apoptotic factors, and regulation of the TLR4‑NF‑κB signaling pathway. Isoquercetin may therefore potentially exert a protective effect against AMI or other heart diseases.

Comparison of treatment outcomes of ticagrelor and clopidogrel among patients undergoing percutaneous coronary intervention: A meta-analysis

We performed a meta-analysis of randomized controlled trials (RCTs) to investigate the efficacy and safety of ticagrelor (TIC) vs. clopidogrel (CLO) in patients undergoing percutaneous coronary intervention (PCI). In Jun 2016, a literature search was started and all the studies were conducted from 2010 to 2015. We systematically searched the literature through the MEDLINE database, Cochrane library, and EMBASE database. Quality assessments were evaluated with Jadad quality scale. Data were extracted considering the characteristics of efficacy and safety designs. Six RCTs enrolling 26 244 participants and satisfying the inclusion criteria were finally analyzed. There was a significant decrease of all-cause mortality (MD=0.83, 95%CI=0.74-0.93, P=0.001) and myocardial infarction (MI) (MD=0.78, 95%CI=0.70-0.88, P=0.000). There were no significant differences in stroke (MD=1.34, 95%CI=0.99-1.79, P=0.06), total bleeding (MD=0.97, 95%CI=0.84-1.12, P=0.66), minor or major bleeding (MD=1.06, 95%CI=0.94-1.19, P=0.35) in patients undergoing PCI after treatment with TIC vs. CLO. TIC could be more significant in decreasing all-cause mortality and MI than CLO, but there were no significant differences between TIC and CLO in inhibiting stroke, major bleeding, major or minor bleeding in patients undergoing PCI.

Effects of ticagrelor on neointimal hyperplasia and endothelial function, compared with clopidogrel and prasugrel, in a porcine coronary stent restenosis model

BACKGROUND

Several investigations have been conducted to evaluate the off-target effects of ticagrelor. The aim of the present study was to evaluate the off-target effects of ticagrelor such as neointimal formation and endothelial function after drug-eluting stent implantation in a porcine restenosis model.

METHODS

A total of 30 pigs were randomly allocated based on the following P2Y₁₂ inhibitor: (1) clopidogrel 300mg loading plus 75mg maintenance (n=10); (2) prasugrel 60mg loading plus 10mg maintenance (n=10); (3) ticagrelor 180mg loading plus 180mg maintenance (n=10). In each group, zotarolimus-eluting stents were implanted in the proximal portion of the left anterior descending artery and left circumflex artery. One month after stenting, the animals underwent follow-up angiography, endothelial function assessment, optical coherence tomography (OCT) and histopathological analysis.

RESULTS

Regarding vasomotor responses to acetylcholine infusion, there were significant vasoconstrictions to maximal acetylcholine infusion in the clopidogrel and prasugrel group compared with those in the ticagrelor group. The mean neointimal area were significantly lower in the ticagrelor group (1.0±0.3 by OCT, 0.9±0.3 by histology), than in the clopidogrel (1.8±0.7, p=0.003, 1.6±0.8, p=0.030) and prasugrel (1.8±0.5, p=0.001, 1.5±0.5, p=0.019) groups. Percentages of moderate to dense peri-strut inflammatory cell infiltration were significantly lower in the ticagrelor group (9.0%) compared with the clopidogrel (17.3%, p<0.001) and prasugrel groups (15.7%, p=0.002). There were no significant differences in all findings between clopidogrel and prasugrel groups.

CONCLUSIONS

Compared to clopidogrel and prasugrel, ticagrelor reduced neointimal formation, endothelial dysfunction, and peri-strut inflammation.