Biochemical aspirin resistance is associated with increased stroke severity and infarct volumes in ischemic stroke patients

Clopidogrel with indobufen or aspirin in minor ischemic stroke or high-risk transient ischemic attack: a randomized controlled clinical study

BACKGROUND

Ischemic stroke and transient ischemic attack (TIA) are the most prevalent cerebrovascular diseases. The conventional antiplatelet drugs are associated with an inherent bleeding risk, while indobufen is a new antiplatelet drug and has the similar mechanism of antiplatelet aggregation as aspirin with more safety profile. However, there have been no studies evaluating the combination therapy of indobufen and clopidogrel for antiplatelet therapy in cerebrovascular diseases.

OBJECTIVE

The CARMIA study aims to investigate the effectiveness and safety of a new dual antiplatelet therapy consisting of indobufen and clopidogrel comparing with the conventional dual antiplatelet therapy consisting of aspirin and clopidogrel in patients with minor ischemic stroke or high-risk TIA.

METHODS

An open-label randomized controlled clinical trial was conducted at a clinical center. We randomly assigned patients who had experienced a minor stroke or transient ischemic attack (TIA) within 72 h of onset, or within 1 month if they had intracranial stenosis (IS), to receive either indobufen 100 mg twice daily or aspirin 100 mg once daily for 21 days. For patients with IS, the treatment duration was extended to 3 months. All patients received a loading dose of 300 mg clopidogrel orally on the first day, followed by 75 mg once daily from the second day to 1 year. We collected prospective data using paper-based case report forms, and followed up on enrolled patients was conducted to assess the incidence of recurrent ischemic stroke or TIA, mRS score, NIHSS (National Institutes of Health Stroke Scale) score, and any bleeding events occurring within 3 month after onset.

RESULTS

We enrolled 202 patients diagnosed with ischemic stroke or transient ischemic attack. After applying the criteria, 182 patients were eligible for data analysis. Endpoint events (recurrence of ischemic stroke/TIA, myocardial infarction, or death) were observed in 6 patients (6.5%) receiving aspirin and clopidogrel, including 4 (4.3%) with stroke recurrence, 1 (1.1%) with TIA recurrence, and 1 (1%) with death. In contrast, no endpoint events were reported in the indobufen and clopidogrel group (P = 0.029). The group of patients receiving indobufen and clopidogrel exhibited significantly lower modified Rankin Scale (mRS) score. (scores range from 0 to 6, with higher scores indicating more severe disability) compared to the aspirin and clopidogrel group (common odds ratio 3.629, 95% CI 1.874-7.036, P < 0.0001). Although the improvement rate of NIHSS score in the indobufen and clopidogrel group was higher than that in the aspirin and clopidogrel group, the difference was not statistically significant (P > 0.05). Bleeding events were observed in 8 patients (8.6%) receiving aspirin and clopidogrel, including 4 (4.3%) with skin bleeding, 2 (2.2%) with gingival bleeding, 1 (1.1%) with gastrointestinal bleeding, and 1 (1.1%) with urinary system bleeding. On the other hand, only 1 patient (1.1%) in the indobufen and clopidogrel group experienced skin bleeding (P = 0.035).

CONCLUSION

The combination of indobufen and clopidogrel has shown non-inferior and potentially superior effectiveness and safety compared to aspirin combined with clopidogrel in patients with minor ischemic stroke and high-risk TIA in the CARMIA study (registered under chictr.org.cn with registration number ChiCTR2100043087 in 01/02/2021).

Analysis and Regulatory Mechanisms of Platelet-Related Genes in Patients with Ischemic Stroke

It was found that ischemic stroke (IS) was associated with abnormal platelet activity and thrombosis. However, the potential significance of platelet-related genes (PRGs) in IS still needs to be more thorough. This study extracted IS-related transcriptome datasets from the Gene Expression Omnibus (GEO) database. The target genes were obtained by intersecting the differentially expressed genes (DEGs), the module genes related to IS, and PRGs, where the key genes of IS were screened by two machine learning algorithms. The key genes-based diagnostic model was constructed. Gene set enrichment analysis (GSEA) and the immune microenvironment analyses were analyzed targeting key genes in IS. The co-expression, TF-mRNA, and competitive endogenous RNAs (ceRNA) regulatory networks were constructed to reveal the potential regulation of key genes. Potential drugs targeting key genes were predicted as well. Totals of eight target genes were obtained and were associated with immune-related functions. Four platelet-related key genes were acquired, which were related to immunity and energy metabolism. The abnormal expressions of DOCK8, GIMAP5, ICOS were determined by the quantitative real-time polymerase chain reaction (qRT-PCR), and the significant correlations among these key genes were identified. Notably, hsa-miR-17-3p, hsa-miR-3158-3p, hsa-miR-423-3p, and hsa-miR-193a-8p could regulate all key genes at the same time. In addition, Caffeine, Carboplatin, and Vopratelimab were the targeted drugs of these key genes. This study identified four platelet-related key genes of IS, which might help to deepen the understanding of the role of platelet-related genes in the molecular mechanism of IS.

Non-coding RNAs in stroke pathology, diagnostics, and therapeutics

Ischemic stroke is a leading cause of death and disability worldwide. Methods to alleviate functional deficits after ischemic stroke focus on restoration of cerebral blood flow to the affected area. However, pharmacological or surgical methods such as thrombolysis and thrombectomy have a narrow effective window. Harnessing and manipulating neurochemical processes of recovery may provide an alternative to these methods. Recently, non-coding RNA (ncRNA) have been increasingly investigated for their contributions to the pathology of diseases and potential for diagnostic and therapeutic applications. Here we will review several ncRNA - H19, MALAT1, ANRIL, NEAT1, pseudogenes, small nucleolar RNA, piwi-interacting RNA and circular RNA - and their involvement in stroke pathology. We also examine these ncRNA as potential diagnostic biomarkers, particularly in circulating blood, and as targets for therapeutic interventions. An important aspect of this is a discussion of potential methods of treatment delivery to allow for targeting of interventions past the blood-brain barrier, including lipid nanoparticles, polymer nanoparticles, and viral and non-viral vectors. Overall, several long non-coding RNA (lncRNA) discussed here have strong implications for the development of pathology and functional recovery after ischemic stroke. LncRNAs H19 and ANRIL show potential as diagnostic biomarkers, while H19 and MALAT1 may prove to be effective therapeutics for both minimising damage as well as promoting recovery. Other ncRNA have also been implicated in ischemic stroke but are currently too poorly understood to make inferences for diagnosis or treatment. Whilst the field of ncRNAs is relatively new, significant work has already highlighted that ncRNAs represent a promising novel investigative tool for understanding stroke pathology, could be used as diagnostic biomarkers, and as targets for therapeutic interventions.

High on-treatment platelet reactivity is associated with poor outcomes after ischemic stroke: A meta-analysis

OBJECTIVES

High on-treatment platelet reactivity (HTPR) determined by platelet function assays is present in certain patients with ischemic stroke or transient ischemic attack (TIA). However, it is unclear whether HTPR is associated with poor clinical outcomes. Our study aimed to investigate the relationship of HTPR with recurrent vascular events in ischemic stroke or TIA.

METHODS

Pubmed (MEDLINE), EMBASE, and Cochrane Library were searched for eligible studies from inception to January 1, 2022. Stata 17.0 software was used to calculate the risk ratio (RR). Subgroup and sensitivity analyses were conducted to assess the source of heterogeneity. A random-effects model was used when heterogeneity was present. Primary endpoint of the meta-analysis was the risk ratio of recurrent vascular events in HTPR Patients. While stroke and TIA, all-cause death, early neurological deterioration, early new ischemic lesions, and stroke severity measured by National Institute of Health Stroke Scale (NIHSS) scores at admission were also pooled.

RESULTS

Thirty articles (7995 patients) were eligible including 28 cohort studies and 2 prospective case-control studies. The prevalence of HTPR varied from 5.9% to 60%. HTPR was associated with an increased risk of recurrent vascular events (RR = 2.94, 95% CI 2.04-4.23), stroke recurrence (RR = 2.05; 95% CI 1.43-2.95), and all-cause mortality (RR = 2.43; 95% CI 1.83-3.22). Subgroup analysis showed that HTPR determined by optical aggregometry, Verify-Now system and 11dh TXB2 is related to a higher risk of recurrent vascular events (RR = 3.53, 95% CI 1.51-9.40; RR = 2.16, 95% CI 1.02-4.56; RR = 3.76, 95% CI 1.51-9.40, respectively). Moreover, patients with HTPR had an increased incidence of early neurological deterioration (RR = 2.75; 95% CI 1.76-4.30) and higher NIHSS scores at admission (Mean difference 0.19, 95% CI 0.01-0.36).

CONCLUSIONS

This meta-analysis demonstrates HTPR is associated with higher risk of recurrent vascular events, early neurological deterioration and increased severity in patients with ischemic stroke and TIA. HTPR measured by platelet function assays may guide the use of antiplatelet agents in ischemic stroke and TIA.

Biomarkers for Antiplatelet Therapies in Acute Ischemic Stroke: A Clinical Review

Stroke is one of the world's leading causes of disability and death. Antiplatelet agents are administered to acute ischemic stroke patients as secondary prevention. Clopidogrel involves biotransformation by cytochrome P450 (CYP) enzymes into an active metabolite, and single nucleotide polymorphisms (SNPs) can influence the efficacy of this biotransformation. Despite the therapeutic advantages of aspirin, there is significant inter-individual heterogeneity in response to this antiplatelet drug. In this clinical review, the recent advances in the biomarkers of antiplatelet agents in acute ischemic stroke are discussed. The studies reviewed herein highlight the clinical relevance of antiplatelet resistance, pharmacotherapy of antiplatelet agents predicting drug response, strategies for identifying aspirin resistance, pharmacogenetic variants of antiplatelet agents, miRNAs, and extracellular vesicles (EVs) as biomarkers toward the personalized approach in the management of acute ischemic stroke. The precise pathways contributing to antiplatelet resistance are not very well known but are presumably multi-factorial. It is essential to understand the clinical relevance of clopidogrel and aspirin-related single nucleotide polymorphism (SNPs) as potential predictive and prognostic biomarkers. Prasugrel is a next-generation antiplatelet agent that prevents ADP-platelet activation by binding irreversibly to P2Y12 receptor. There are sporadic reports of prasugrel resistance and polymorphisms in the Platelet endothelial aggregation receptor-1 (PEAR1) that may contribute to a change in the pharmacodynamics response. Ticagrelor, a direct-acting P2Y12-receptor antagonist, is easily absorbed and partly metabolized to major AR-C124910XX metabolite (ARC). Ticagrelor's primary active metabolite, ARC124910XX (ARC), is formed via the most abundant hepatic cytochrome P450 (CYP) enzyme, CYP3A4, and CYP3A5. The integration of specific biomarkers, genotype as well as phenotype-related data in antiplatelet therapy stratification in patients with acute ischemic stroke will be of great clinical significance and could be used as a guiding tool for more effective, personalized therapy.

Unfavorable Changes of Platelet Reactivity on Clopidogrel Therapy Assessed by Impedance Aggregometry Affect a Larger Volume of Acute Ischemic Lesions in Stroke

Background: High on-treatment platelet reactivity or its equivalent—resistance to the antiplatelet agent—significantly reduces the efficacy of the therapy, contributing to a negative impact on stroke course. Previous studies demonstrated that aspirin resistance is associated with a larger size of acute ischemic infarct. Due to the increasing use of clopidogrel in the secondary prevention of stroke, we aimed to assess the impact of clopidogrel resistance on the size and extent of ischemic lesions, both acute and chronic. Methods: This prospective, single-center and observational study involved 74 ischemic stroke subjects, treated with 75 mg of clopidogrel. We used impedance aggregometry to determine platelet reactivity 6–12 h after a dose of clopidogrel as a first assessment and 48 h later as the second measurement. A favorable dynamics of platelet reactivity over time was the decrease in the minimum value equal to the median in the entire study. The volume of acute ischemic infarct was estimated within 48 h after onset in diffusion-weighted imaging and fluid-attenuated inversion recovery sequences of magnetic resonance and the severity of chronic vascular lesions by Fazekas scale. Results: Subjects with mild severity of chronic vascular lesions (Fazekas 1) exhibited a significant decrease of platelet reactivity over time (p = 0.035). Dynamics of platelet reactivity over time differed between subjects with large, moderate, mild and insignificant size of acute ischemic lesion (Kruskall-Wallis H = 3.2576; p = 0.048). In multivariate regression models, we reported unfavorable dynamics of platelet reactivity alone and combined with a high initial value of platelet reactivity as independent predictors of higher risk of a significant ischemic infarct volume (OR 7.16 95%CI 1.69–30.31, p = 0.008 and 26.49 95%CI 1.88–372.4, p = 0.015, respectively). Conclusions: We emphasized that unfavorable dynamics of platelet reactivity over time during clopidogrel therapy in acute phase of stroke affect the volume of acute infarct and the severity of chronic vascular lesions.

Unfavorable Dynamics of Platelet Reactivity during Clopidogrel Treatment Predict Severe Course and Poor Clinical Outcome of Ischemic Stroke

Background: Previous studies have revealed that high platelet reactivity while on clopidogrel may affect the severe course and worse prognosis of ischemic stroke. However, the above findings were based on a single measurement of platelet function. We aimed to investigate whether the dynamics of platelet reactivity over time would more accurately determine its actual impact on clinical outcome. Methods: We enrolled 74 ischemic stroke subjects, taking a dose of 75 mg a day of clopidogrel to this prospective, single-center, and observational study. The determination of platelet function was based on the impedance aggregometry 6–12 h after the first dose of clopidogrel and 48 h later. We defined a favorable dynamics of platelet reactivity as a decrease in values at least equal to the median obtained in the entire study. The clinical condition was assessed by the National Institutes of Health Stroke Scale on the first, third, and ninetieth days and the functional status by modified Rankin Scale, respectively. Results: A favorable dynamics of platelet reactivity was associated with the mild clinical condition and favorable functional status, both early and late. Early neurological deterioration was related to unfavorable dynamics of platelet reactivity over time. In multivariate regression models, we found that unfavorable dynamics of platelet reactivity, alone and combined with a high baseline value of platelet reactivity, is an independent predictor of a severe clinical condition, the risk of deterioration, and poor early and late prognosis. Conclusion: We highlighted that dynamics of platelet reactivity over time predict the clinical course and prognosis of stroke better than a single value.

Multifactorial Background for a Low Biological Response to Antiplatelet Agents Used in Stroke Prevention

Effective platelet inhibition is the main goal of the antiplatelet therapy recommended as a standard treatment in the secondary prevention of non-embolic ischemic stroke. Acetylsalicylic acid (aspirin) and clopidogrel are commonly used for this purpose worldwide. A low biological response to antiplatelet agents is a phenomenon that significantly reduces the therapeutic and protective properties of the therapy. The mechanisms leading to high on-treatment platelet reactivity are still unclear and remain multifactorial. The aim of the current review is to establish the background of resistance to antiplatelet agents commonly used in the secondary prevention of ischemic stroke and to explain the possible mechanisms. The most important factors influencing the incidence of a low biological response were demonstrated. The similarities and the differences in resistance to both drugs are emphasized, which may facilitate the selection of the appropriate antiplatelet agent in relation to specific clinical conditions and comorbidities. Despite the lack of indications for the routine assessment of platelet reactivity in stroke subjects, this should be performed in selected patients from the high-risk group. Increasing the detectability of low antiaggregant responders, in light of its negative impact on the prognosis and clinical outcomes, can contribute to a more individualized approach and modification of the antiplatelet therapy to maximize the therapeutic effect in the secondary prevention of stroke.

Long Non-Coding RNA H19 Positively Associates With Aspirin Resistance in the Patients of Cerebral Ischemic Stroke

Background and purpose

Aspirin is a novel anti-platelet drug that is intensively recommended for the prevention and treatment of cerebral ischemic stroke. However, the existence of aspirin resistance weakens the effects of aspirin and usually induces the recurrence of ischemic stroke. While the mechanism underlying aspirin resistance is still unclear. Long non-coding RNA H19 (H19) is closely associated with the onset and prognosis of cerebral ischemic stroke. Since the relationship between H19 and aspirin resistance have never been reported, herein, we aimed to evaluate the H19 expression in aspirin-resistant ischemic stroke patients and subsequently, ascertain the ability of H19 to diagnose aspirin resistance.

Methods

We included 150 patients with acute cerebral ischemic stroke who were followed up for one year to determine stroke recurrence. Levels of 11-dehydro thromboxane B2 (11dhTXB2) in urine were tested to evaluate the status of aspirin resistance, and those of H19 and 8-iso-prostaglandin-2α in plasma were assessed. The relationship between 11dhTXB2 or and 8-iso-prostaglandin-2α and H19, and the receiver operating characteristic curve of H19, the association of H19 and aspirin resistance with the recurrence of stoke were statistically analyzed.

Results

Plasma H19 was significantly up-regulated in patients with aspirin resistance (p=0.0203), and the H19 levels were positively associated with urine 11dhTXB2/creatinine (R=0.04364, p=0.0106) and positively associated with the level of 8-iso-PGF2α (R=0.04561, p=0.0089). The ROC curves indicated that H19 can sensitively and specifically diagnose aspirin resistance (area under the curve, 0.8005; 95% CI, 0.7301–0.8710; p < 0.0001; specificity, 75.86207%; sensitivity, 73.84615%.). H19 is an independent risk factor for aspirin resistance (OR=1.129, p=0.0321), and aspirin resistance and H19 are closely related with ischemic stroke recurrence.

Conclusions

H19 is closely associated with aspirin resistance, and H19 probably induces aspirin resistance through increasing the production of 8-iso-prostaglandin-2α. Besides which, H19 may serve as a serological marker for diagnosing aspirin resistance with high specificity and sensitivity, and the test of H19 could give clues to the recurrence of ischemic stroke.

The Prognostic Value of High Platelet Reactivity in Ischemic Stroke Depends on the Etiology: A Pilot Study

Background: Reduced aspirin response may result in a worse prognosis and a poor clinical outcome in ischemic stroke. The aim of this prospective pilot study was to assess the relationship between platelet reactivity and early and late prognosis, and the clinical and functional status in ischemic stroke, with the role of stroke etiology. Methods: The study involved 69 subjects with ischemic stroke, divided into large and small vessel etiological subgroups. Platelet function testing was performed with two aggregometric methods—impedance and optical—while the clinical condition was assessed using the National Institute of Health Stroke Scale (NIHSS) and the functional status was assessed using the modified Rankin Scale (mRS) on the first and eighth day (early prognosis) and the 90th day of stroke (late prognosis). Results: The initial platelet reactivity was found to be higher in patients with severe neurological deficits on the 90th day after stroke, than in the group with mild neurological deficits (median, respectively, 40 area under the curve (AUC) units vs. 25 AUC units, p = 0.033). In the large vessel disease group, a significant correlation between the platelet reactivity and the functional status on the first day of stroke was found (correlation coefficient (R) = 0.4526; p = 0.0451), the platelet reactivity was higher in the subgroup with a severe clinical condition compared to a mild clinical condition on the first day of stroke (p = 0.0372), and patients resistant to acetylsalicylic acid (aspirin) had a significantly greater possibility of a severe neurological deficit on the first day of stroke compared to those who were sensitive to aspirin (odds ratio (OR) = 14.00, 95% confidence interval (CI) 1.25–156.12, p = 0.0322). Conclusion: High on-treatment platelet reactivity in ischemic stroke was associated with a worse late prognosis regardless of the etiology. We demonstrated a significant relationship between high platelet reactivity and worse early prognosis and poor clinical and functional condition in the large vessel etiologic subgroup. However, due to the pilot nature of this study, its results should be interpreted with caution and further validation on a larger cohort is required.

Association of aspirin resistance with 4-hydroxynonenal and its impact on recurrent cerebral infarction in patients with acute cerebral infarction

OBJECTIVES

To investigate the association of aspirin resistance (AR) with the plasma 4-hydroxynonenal (4-HNE) level and its impact on recurrent cerebral infarction (CI) in patients with acute cerebral infarction (ACI) who were receiving aspirin therapy.

METHODS

One hundred and fifty-four ACI patients who previously received aspirin therapy (100 mg/day) were enrolled. Whole urine (for measuring 11dhTXB2 and creatinine) along with blood (for measuring the plasma 4-HNE level) were collected at least 7 days after the patients received aspirin. A cutoff of 1500 pg/mg of 11dhTXB2/ creatinine was used to determine AR. A follow-up period to monitor recurrence CI events was 1 year. In addition, blood testing was performed when the patients were first admitted to hospital.

RESULTS

Forty-six of the 154 enrolled patients (29.9%) were found to be AR. No statistical difference in age, sex, hypertension, diabetes mellitus, coronary disease, smoking status, NIHSS score, TOAST classification, platelet count, thrombocytocrit, LDL-C, HDL-C, TG, and TC was found between the AR and aspirin-sensitive (AS) patients, but the plasma 4-HNE level was found to be higher in the AR patients than AS patients (p < .05). Multiple logistic regression analysis showed that the 4-HNE level was associated with a higher risk of AR (OR = 1.034; 95% CI = 1.011-1.058; p < .05). Moreover, 1-year follow-up showed that AR was more prevalent in patients with recurrent CI (26 (56.6%)) than those without (20/(43.5%)) (p < .001).

CONCLUSIONS

The plasma 4-HNE level is strongly associated with AR and thus may be a factor contributing to AR. Patients with AR have a greater risk of recurrence CI.

High On-Treatment Platelet Reactivity Affects the Extent of Ischemic Lesions in Stroke Patients Due to Large-Vessel Disease

Background: Excessive platelet activation and aggregation plays an important role in the pathogenesis of ischemic stroke. Correlation between platelet reactivity and ischemic lesions in the brain shows contradictory results and there are not enough data about the potential role of stroke etiology and its relationships with chronic lesions. The aim of this study is to assess the relationship between platelet reactivity and the extent of ischemic lesions with the particular role of etiopathogenesis. Methods: The study involved 69 patients with ischemic stroke, including 20 patients with large-vessel disease and 49 patients with small-vessel disease. Evaluation of platelet reactivity was performed within 24 h after the onset of stroke using two aggregometric methods (impedance and optical), while ischemic volume measurement in the brain was performed using magnetic resonance imaging (in diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences) at day 2–5 after the onset of stroke. Results: In the large-vessel disease subgroup, a correlation was found between platelet reactivity and acute ischemic focus volume (correlation coefficient (R) = 0.6858 and p = 0.0068 for DWI; R = 0.6064 and p = 0.0215 for FLAIR). Aspirin-resistant subjects were significantly more likely to have a large ischemic focus (Odds Ratio (OR) = 45.00, 95% Confidence Interval (CI) = 1.49–135.36, p = 0.0285 for DWI; OR = 28.00, 95% CI = 1.35–58.59, p = 0.0312 for FLAIR) than aspirin-sensitive subjects with large-vessel disease. Conclusion: In patients with ischemic stroke due to large-vessel disease, high on-treatment platelet reactivity affects the extent of acute and chronic ischemic lesions.