Does Uncontrolled Platelet Activation Promote Coronary Artery Disease?

Thrombus architecture is influenced by the antiplatelet loading treatment in patients with acute myocardial infarction

BACKGROUND

Intracoronary thrombus formation is a main cause of acute myocardial infarction triggered by platelet activation. However, there are no data on the impact of different treatment strategies with antiplatelet agents before percutaneous coronary intervention (PCI) on histological characteristics of thrombus formation.

OBJECTIVE

In this study, we investigate the impact of preinterventional administration of the P2Y12-inhibitors clopidogrel and prasugrel on thrombus composition, highlighting significant changes associated with the antiplatelet pre-treatment.

METHODS

We prospectively enrolled 104 consecutive patients with ST-segment elevation myocardial infarction (STEMI) undergoing immediate PCI and thrombus aspiration by immunohistochemical staining along with RNA-sequencing employing Nanostring analysis. Fifty-two patients were treated with either prasugrel loading (60 mg) or clopidogrel loading (600 mg) prior to PCI, respectively.

RESULTS

In Patients with STEMI, intracoronary thrombus architecture was significantly altered between patients pre-treated with prasugrel when compared to clopidogrel. Fibrin content of thrombi was significantly decreased (41.8 % versus 66.7 %, p = 0.009) after pre-treatment with prasugrel compared to clopidogrel. Furthermore, levels of MPO positive cells in intracoronary thrombi were significantly decreased in patients with prasugrel pre-treatment (90.5 versus 201.1, p = 0.014) indicating an association of antiplatelet pre-treatment and the inflammatory responses during thrombus formation. Most strikingly, we observed significant differences among both pre-treatment groups regarding altered RNA expression and signaling pathways of thrombo-inflammatory processes within the thrombotic material, which were independently associated with antiplatelet strategies.

CONCLUSIONS

Our study elucidates the impact of antiplatelet pre-treatment on thrombus remodeling and architecture, thereby lowering the risk of recurrent adverse cardiovascular events in prasugrel-treated patients.

Statin Treatment Is Associated with Alterations in the Platelet Lipidome

BACKGROUND

 Platelets are key players in the pathophysiology of coronary artery disease (CAD) and platelet hyperreactivity leads to increased risk of developing adverse cardiovascular events. Further, significant changes in the platelet lipidome occur in patients with acute coronary syndrome (ACS) and critically regulated lipids lead to platelet hyperresponsiveness. Statin treatment is crucial in the treatment and prevention of patients with CAD by remodeling lipid metabolism.

OBJECTIVE

 In this study, we investigate the platelet lipidome of CAD patients by untargeted lipidomics, highlighting significant changes between statin-treated and naïve patients.

METHODS

 We characterized the platelet lipidome in a CAD cohort (n = 105) by an untargeted lipidomics approach using liquid chromatography coupled to mass spectrometry.

RESULTS

 Among the annotated lipids, 41 lipids were significantly upregulated in statin-treated patients, whereas 6 lipids were downregulated compared to naïve patients. The most prominent upregulated lipids in statin-treated patients belong to the class of triglycerides, cholesteryl esters, palmitic acid, and oxidized phospholipids, whereas mainly glycerophospholipids were downregulated compared to untreated patients. A more pronounced effect of statin treatment on the platelet lipidome was observed in ACS patients. We further highlight a dose-dependent influence on the platelet lipidome.

CONCLUSION

 Our results reveal that the platelet lipidome is altered in CAD patients with statin treatment and upregulated lipids embody mainly characteristic triglycerides, whereas downregulated lipids mostly compromise glycerophospholipids, which may play a role in the pathophysiology of CAD. Results of this study may contribute to the understanding of statin treatment softening the lipid phenotype.

A Signature for Smoking Status of Coronary Heart Disease Patients through Weighted Gene Coexpression Network Analysis

Background. Smoking is one of the risk factors of coronary heart disease (CHD), while its underlying mechanism is less well defined. Purpose. To identify and testify 6 key genes of CHD related to smoking through weighted gene coexpression network analysis (WGCNA), protein-protein interaction (PPI) network analysis, and pathway analysis. Methods. CHD patients’ samples were first downloaded from Gene Expression Omnibus (GEO). Then, genes of interest were obtained after analysis of variance (ANOVA). Thereafter, 23 coexpressed modules that were determined after genes with similar expression were incorporated via WGCNA. The biological functions of genes in the modules were researched by enrichment analysis. Pearson correlation analysis and PPI network analysis were used to screen core genes related to smoking in CHD. Results. The violet module was the most significantly associated with smoking ( $r=-0.28$ , $p=0.006$ ). Genes in this module mainly participated in biological functions related to the heart. Altogether, 6 smoking-related core genes were identified through bioinformatics analyses. Their expressions in animal models were detected through the animal experiment. Conclusion. This study identified 6 core genes to serve as underlying biomarkers for monitoring and predicting smoker’s CHD risk.

Acute coronary syndrome is associated with a substantial change in the platelet lipidome

AIMS

Platelets play a key role in the pathophysiology of coronary artery disease (CAD) and patients with enhanced platelet activation are at increased risk to develop adverse cardiovascular events. Beyond reliable cardiovascular risk factors such as dyslipoproteinaemia, significant changes of platelet lipids occur in patients with CAD. In this study, we investigate the platelet lipidome by untargeted liquid chromatography-mass spectrometry, highlighting significant changes between acute coronary syndrome (ACS) and chronic coronary syndrome (CCS) patients. Additionally, we classify the platelet lipidome, spotlighting specific glycerophospholipids as key players in ACS patients. Furthermore, we examine the impact of significantly altered lipids in ACS on platelet-dependent thrombus formation and aggregation.

METHODS AND RESULTS

In this consecutive study, we characterized the platelet lipidome in a CAD cohort (n = 139) and showed significant changes of lipids between patients with ACS and CCS. We found that among 928 lipids, 7 platelet glycerophospholipids were significantly up-regulated in ACS, whereas 25 lipids were down-regulated compared to CCS. The most prominent up-regulated lipid in ACS, PC18:0 (PC 10:0-8:0), promoted platelet activation and ex vivo platelet-dependent thrombus formation.

CONCLUSIONS

Our results reveal that the platelet lipidome is altered in ACS and up-regulated lipids embody primarily glycerophospholipids. Alterations of the platelet lipidome, especially of medium chain lipids, may play a role in the pathophysiology of ACS.