Epoxidase inhibitor-aspirin resistance and the relationship with genetic polymorphisms: a review

Strokes are the leading cause of death in most regions of the world. Epoxidase inhibitors include the drug aspirin (acetylsalicylic acid). Aspirin is widely used as first-line treatment for the prevention of cardiovascular and cerebrovascular diseases in at-risk patients. However, patients using conventional doses of aspirin can still develop ischaemic cardiovascular and cerebrovascular diseases, a phenomenon known as aspirin resistance. The occurrence of aspirin resistance hinders the prevention and treatment of ischaemic cardiovascular and cerebrovascular diseases. There are many factors affecting aspirin resistance, such as sex, drug dose, metabolic disease, genetic polymorphisms, drug interactions and pharmacokinetics. Genetic polymorphism refers to the simultaneous and frequent presence of two or more discontinuous variants or genotypes or alleles in a population of organisms. Platelets contain a large number of highly polymorphic transmembrane glycoprotein receptors encoded by two or more isomeric alleles. Changes in gene polymorphisms in various pathways during platelet aggregation can lead to aspirin resistance. This narrative review describes the gene polymorphisms that have been demonstrated to be significantly associated with aspirin resistance. Research on the mechanisms of aspirin resistance and increased knowledge should provide accurate drug guidance in individuals that require first-line antiplatelet therapy.

In silico identification of molecular mechanisms for stroke risk caused by heavy metals and their mixtures: sponges and drugs involved

This study used various approaches and databases to evaluate the molecular processes and identify miRNA sponges and drugs associated with the development of stroke caused by heavy metals and their combinations. We found that the genes ALB (albumin), IL1B (Interleukin-1β), F2 (coagulation factor II), APOA1 (apolipoprotein A1), IL6 (Interleukin 6), and NOS2 (nitric oxide synthase 2) were linked to the development of strokes by 18 chemicals and a combination of cadmium, copper, and lead. These results may point to the significance of detoxification and neuroinflammation in stroke as well as the potential for targeting these genes in future stroke therapies. ALB and IL1B were the most common and significant genes. The "selenium micronutrient network," "vitamin B12 metabolism," and "folate metabolism" were shown to be the most significant pathways connected to the risk of stroke brought on by combined heavy metals. The two main cellular elements that may increase the risk of stroke caused by heavy metals were discovered to be "blood microparticle" and "endoplasmic reticulum lumen." We also observed an important chromosome (chr7p15.3), two transcription factors (NFKB2 [nuclear factor kappa B subunit 2] and NR1I2 [nuclear receptor subfamily 1 group, member 2]), and four microRNAs (hsa-miR-26a-5p, hsa-miR-9-5p, hsa-miR-124-3p, and hsa-miR-155-5p) associated with stroke caused by combined heavy metals. Additionally, for these miRNAs, we created and examined in silico microRNA sponge sequences. Triflusal and andrographolide have been identified as potential treatments for heavy metal-induced stroke. Taken together, heavy metals may be a significant contributor to the pathophysiology of stroke, but further investigation into the precise molecular pathways implicated in stroke pathophysiology is required to corroborate these findings.

Analysis of Time Series Gene Expression and DNA Methylation Reveals the Molecular Features of Myocardial Infarction Progression

Myocardial infarction (MI) is one of the deadliest diseases in the world, and the changes at the molecular level after MI and the DNA methylation features are not clear. Understanding the molecular characteristics of the early stages of MI is of significance for the treatment of the disease. In this study, RNA-seq and MeDIP-seq were performed on heart tissue from mouse models at multiple time points (0 h, 10 min, 1, 6, 24, and 72 h) to explore genetic and epigenetic features that influence MI progression. Analysis based on a single point in time, the number of differentially expressed genes (DEGs) and differentially methylated regions (DMRs) increased with the time of myocardial infarction, using 0 h as a control group. Moreover, within 10 min of MI onset, the cells are mainly in immune response, and as the duration of MI increases, apoptosis begins to occur. Analysis based on time series data, the expression of 1012 genes was specifically downregulated, and these genes were associated with energy metabolism. The expression of 5806 genes was specifically upregulated, and these genes were associated with immune regulation, inflammation and apoptosis. Fourteen transcription factors were identified in the genes involved in apoptosis and inflammation, which may be potential drug targets. Analysis based on MeDIP-seq combined with RNA-seq methodology, focused on methylation at the promoter region. GO revealed that the downregulated genes with hypermethylation at 72 h were enriched in biological processes such as cardiac muscle contraction. In addition, the upregulated genes with hypomethylation at 72 h were enriched in biological processes, such as cell-cell adhesion, regulation of the apoptotic signaling pathway and regulation of angiogenesis. Among these genes, the Tnni3 gene was also present in the downregulated model. Hypermethylation of Tnni3 at 72 h after MI may be an important cause of exacerbation of MI.

Effects of Triflusal and Clopidogrel on the Secondary Prevention of Stroke Based on Cytochrome P450 2C19 Genotyping

Background and Purpose

To compare the efficacy and safety of antiplatelet agents for the secondary prevention of ischemic stroke based on cytochrome P450 2C19 (CYP2C19) polymorphisms.

Methods

This study was a prospective, multicenter, randomized, parallel-group, open-label, blind genotype trial. First time non-cardiogenic ischemic stroke patients were enrolled and screened within 30 days. Participants were randomized to receive either triflusal or clopidogrel for secondary stroke prevention. The primary outcome was the time from randomization to first recurrent ischemic stroke or hemorrhagic stroke.

Results

The required sample size was 1,080 but only 784 (73%) participants were recruited. In patients with a poor CYP2C19 genotype for clopidogrel metabolism (n=484), the risk of recurrent stroke among those who received triflusal treatment was 2.9% per year, which was not significantly different from those who received clopidogrel treatment (2.2% per year; hazard ratio [HR], 1.23; 95% confidence interval [CI], 0.60–2.53). In the clopidogrel treatment group (n=393), 38% had good genotypes and 62% poor genotypes for clopidogrel metabolism. The risk of recurrent stroke in patients with a good CYP2C19 genotype was 1.6% per year, which was not significantly different from those with a poor genotype (2.2% per year; HR, 0.69; 95% CI, 0.26–1.79).

Conclusions

Whilst there were no significant differences between the treatment groups in the rates of stroke recurrence, major vascular events, or coronary revascularization, the efficacy of antiplatelet agents for the secondary prevention of stroke according to CYP2C19 genotype status remains unclear.

Digestive and urologic hemorrhage after intravenous thrombolysis for acute ischemic stroke: Data from a Chinese stroke center

Objective

Intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) is considered the most effective treatment method for AIS; however, it is associated with a risk of hemorrhage. We analyzed the risk factors for digestive and urologic hemorrhage during rt-PA therapy.

Methods

We retrospectively analyzed patients with AIS who underwent intravenous thrombolysis with rt-PA during a 5-year period in a Chinese stroke center. Data on the demographics, medical history, laboratory test results, and clinical outcomes were collected.

Results

338 patients with AIS were eligible and included. Logistic regression multivariate analysis showed that gastric catheter was significantly correlated with digestive hemorrhage, while age and urinary catheter were significantly correlated with urologic hemorrhage. Most hemorrhagic events were associated with catheterization after 1 to 24 hours of rt-PA therapy.

Conclusions

In summary, gastric and urinary catheters were correlated with digestive and urologic hemorrhage in patients with AIS undergoing rt-PA therapy. Well-designed controlled studies with large samples are required to confirm our findings.

Neuroprotective effect of triflusal and its main metabolite, 2-hydroxy-4-trifluoromethylbenzoic acid (HTB), in the postischemic brain

2-Hydroxy-4-trifluoromethylbenzoic acid (HTB) is a metabolite of triflusal (TF), and has been reported to exert anti-inflammatory effect. In this study, the authors investigated whether HTB has a neuroprotective effect against ischemic brain injuries. We showed that intravenous administration of HTB (5mg/kg) 30min before or 1, 3, or 6h after middle cerebral artery occlusion (MCAO) reduced brain infarct to 10.4±3.3%, 16.9±2.3%, 22.2±1.5% and 40.7±7.5%, respectively, of that of treatment-naive MCAO controls, and the therapeutic time window extended to 9h after MCAO (40.7±7.5%). Furthermore, HTB suppressed infarct formation, protected motor activities, and ameliorated neurological deficits more effectively than by TF or salicylic acid (SA). HTB markedly suppressed microglial activation and proinflammatory cytokines expressions in the postischemic brain and in BV2 cells and suppressed LPS-induced nitrite production by inhibiting IkB degradation. In addition, HTB suppressed NMDA-induced neuronal cell death more effectively than TF or SA in primary cortical neuron cultures. Together, these results indicate that HTB has multi-modal protective effects against ischemic brain damage that encompass anti-inflammatory, anti-excitotoxicity, and anti-Zn²⁺-toxicity effects.

Robust neuroprotective effects of 2-((2-oxopropanoyl)oxy)-4-(trifluoromethyl)benzoic acid (OPTBA), a HTB/pyruvate ester, in the postischemic rat brain

Postischemic brain damage in stroke is proceded with complicated pathological events, and so multimodal drug treatments may offer better therapeutic means for improving clinical outcomes. Here, we report robust neuroprotective effects of a novel compound, 2-((2-oxopropanoyl)oxy)-4-(trifluoromethyl)benzoic acid (OPTBA), a 2-hydroxy-4-trifluoromethyl benzoic acid (HTB, a metabolite of triflusal)-pyruvate ester. Intravenous administration of OPTBA (5 mg/kg) 3 or 6 h after middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats reduced infarct volumes to 38.5 ± 11.4% and 46.5 ± 15.3%, respectively, of that of MCAO controls, and ameliorated motor impairment and neurological deficits. Importantly, neuroprotective effects of OPTBA were far greater than those afforded by combined treatment of HTB and pyruvate. Furthermore, OPTBA suppressed microglial activation and proinflammatory cytokine inductions more effectively than HTB/pyruvate co-treatment in the postischemic brain and LPS-treated cortical slice cultures and also attenuated NMDA-induced neuronal death in hippocampal slice cultures. LC-MS analysis demonstrated that OPTBA was hydrolyzed to HTB and pyruvate with a t_1/2 of 38.6 min in blood and 7.2 and 2.4 h in cortex and striatum, respectively, and HTB was maintained for more than 24 h both in blood and brain tissue. Together these results indicate OPTBA acts directly and via its hydrolysis products, thus acting as a multimodal neuroprotectant in the postischemic brain.

Protocol for the comparison of triflusal and clopidogrel in secondary prevention of stroke based on cytochrome P450 2C19 genotyping (MASETRO study): A multicenter, randomized, open-label, parallel-group trial

RATIONALE AND AIM

The antiplatelet effect of clopidogrel is reportedly influenced by cytochrome P450 2C19 (CYP2C19) polymorphisms. However, there is no data concerning the relationship between stroke recurrence and CYP2C19 polymorphisms in patients treated with clopidogrel for secondary prevention of ischemic stroke. Triflusal may be an alternative therapy for clopidogrel in patients with poor genotype. The Comparison of Triflusal and Clopidogrel Effects in Secondary Prevention of Stroke Based on Cytochrome P450 2C19 Genotyping (MAESTRO) study will investigate the effect of antiplatelet agents based on CYP2C19 polymorphisms in secondary prevention of ischemic stroke.

SAMPLE SIZE AND DESIGN

Assuming that 55% of patients belong to the poor genotype group, the required sample size is 1080 patients with at least 24 months of follow-up. This study is designed as a prospective, multicenter, randomized, parallel-group, open-label, and blind genotype trial. Patients who experience their first non-cardiogenic ischemic stroke within 30 days prior to screening are eligible. Patients received 300 mg triflusal twice a day or 75 mg clopidogrel once daily during the trial. The study is registered with ClinicalTrials.gov (NCT01174693).

STUDY OUTCOME

The primary outcome is recurrent ischemic stroke or hemorrhagic stroke. Secondary outcomes consist of composite major vascular events including stroke, myocardial infarction, coronary revascularization, or vascular death.

DISCUSSION

Personalized medicine may be essential for patients according to individual drug metabolism abilities. MAESTRO is the first prospective study designed to evaluate the effect of CYP2C19 polymorphism in secondary stroke prevention and will resolve several questions regarding preventive antiplatelet agents for recurrent stroke.

Current state and novel approaches of antiplatelet therapy

An unresolved problem with clinical use of antiplatelet therapy is that a significant number of individuals either still get thrombosis or run the risk of life-threatening bleeding. Antiplatelet drugs are widely used clinically, either chronically for people at risk of athero/thrombotic disease or to prevent thrombus formation during surgery. However, a subpopulation may be resistant to standard doses, while the platelet targets of these drugs are also critical for the normal hemostatic function of platelets. In this review, we will briefly examine current antiplatelet therapy and existing targets while focusing on new potential approaches for antiplatelet therapy and improved monitoring of effects on platelet reactivity in individuals, ultimately to improve antithrombosis with minimal bleeding. Primary platelet adhesion-signaling receptors, glycoprotein (GP)Ib-IX-V and GPVI, that bind von Willebrand factor/collagen and other prothrombotic factors are not targeted by drugs in clinical use, but they are of particular interest because of their key role in thrombus formation at pathological shear.