Circulating CX3CR1+CD163+ M2 monocytes markedly elevated and correlated with cardiac markers in patients with acute myocardial infarction

Persistence of a proinflammatory status after treatment of the acute myocardial infarction

AIM

To evaluate the lipid-lowering and antiplatelet combined strategies on the expression of the receptors CCR2, CCR5, and CX3CR1 and the percentage of CCR2, CCR5, and CX3CR1 cells in monocyte subtypes after acute myocardial infarction.

METHODS

Prospective, randomized, open-label study, with blinded analyses of endpoints (PROBE, ClinicalTrials.gov Identifier: NCT02428374, registration date: April 28, 2015). Participants were treated with rosuvastatin 20 mg or simvastatin 40 mg plus ezetimibe 10 mg, as well as ticagrelor 90 mg or clopidogrel 75 mg. The chemokine receptors CCR2, CCR5, and CX3CR1 were analyzed by real-time polymerase chain reaction as well as the percentages of CCR2, CCR5, and CX3CR1 cells in the monocyte subtypes (classical, intermediate, and non-classical), which were quantified by flow cytometry, at baseline, and after 1 and 6 months of treatment.

RESULTS

After comparisons between the three visits, regardless of the treatment arm, there was an increase in CCR2 expression after treatment, as well as an increase in intermediate monocytes CCR2+ and a reduction in non-classical monocytes CCR2+ at the end of treatment. There was also a lower expression of CCR5 after treatment and an increase in classical and non-classical monocytes CCR5+. Concerning CX3CR1, there were no differences in the expression after treatment; however, there were reductions in the percentage of intermediate and non-classical monocytes CX3CR1+ at the end of treatment.

CONCLUSIONS

The results suggest the persistence of the inflammatory phenotype, known as trained immunity, even with the highly-effective lipid-lowering and antiplatelet therapies. Geriatr Gerontol Int 2023; 23: 700-707.

Identification of immune-related biomarkers co-occurring in acute ischemic stroke and acute myocardial infarction

Background

Acute ischemic stroke (AIS) and acute myocardial infarction (AMI) share several features on multiple levels. These two events may occur in conjunction or in rapid succession, and the occurrence of one event may increase the risk of the other. Owing to their similar pathophysiologies, we aimed to identify immune-related biomarkers common to AIS and AMI as potential therapeutic targets.

Methods

We identified differentially expressed genes (DEGs) between the AIS and control groups, as well as AMI and control groups using microarray data (GSE16561 and GSE123342). A weighted gene co-expression network analysis (WGCNA) approach was used to identify hub genes associated with AIS and/or AMI progression. The intersection of the four gene sets identified key genes, which were subjected to functional enrichment and protein-protein interaction (PPI) network analyses. We confirmed the expression levels of hub genes using two sets of gene expression profiles (GSE58294 and GSE66360), and the ability of the genes to distinguish patients with AIS and/or AMI from control patients was assessed by calculating the receiver operating characteristic values. Finally, the investigation of transcription factor (TF)-, miRNA-, and drug-gene interactions led to the discovery of therapeutic candidates.

Results

We identified 477 and 440 DEGs between the AIS and control groups and between the AMI and control groups, respectively. Using WGCNA, 2,776 and 2,811 genes in the key modules were identified for AIS and AMI, respectively. Sixty key genes were obtained from the intersection of the four gene sets, which were used to identify the 10 hub genes with the highest connection scores through PPI network analysis. Functional enrichment analysis revealed that the key genes were primarily involved in immunity-related processes. Finally, the upregulation of five hub genes was confirmed using two other datasets, and immune infiltration analysis revealed their correlation with certain immune cells. Regulatory network analyses indicated that GATA2 and hsa-mir-27a-3p might be important regulators of these genes.

Conclusion

Using comprehensive bioinformatics analyses, we identified five immune-related biomarkers that significantly contributed to the pathophysiological mechanisms of both AIS and AMI. These biomarkers can be used to monitor and prevent AIS after AMI, or vice versa.

Arginase 1 is upregulated at admission in patients with ST-elevation myocardial infarction

BACKGROUND

The mechanisms underlying rupture of a coronary atherosclerotic plaque and development of myocardial ischemia-reperfusion injury in ST-elevation myocardial infarction (STEMI) remain unresolved. Increased arginase 1 activity leads to reduced nitric oxide (NO) production and increased formation of reactive oxygen species due to uncoupling of the NO-producing enzyme endothelial NO synthase (eNOS). This contributes to endothelial dysfunction, plaque instability and increased susceptibility to ischemia-reperfusion injury in acute myocardial infarction.

OBJECTIVE

The purpose of this study was to test the hypothesis that arginase gene and protein expression are upregulated in patients with STEMI.

METHODS

Two cohorts of patients with STEMI were included. In the first cohort (n = 51), expression of arginase and NO-synthases as well as arginase 1 protein levels were determined and compared to a healthy control group (n = 45). In a second cohort (n = 68), plasma arginase 1 levels and infarct size were determined using cardiac magnetic resonance imaging.

RESULTS

Expression of the gene encoding arginase 1 was significantly elevated at admission and 24-48 h after STEMI but not 3 months post STEMI, in comparison with the control group. Expression of the genes encoding arginase 2 and endothelial NO synthase (NOS3) were unaltered. Arginase 1 protein levels were elevated at admission, 24 h post STEMI and remained elevated for up to 6 months. No significant correlation between plasma arginase 1 protein levels and infarct size was observed.

CONCLUSION

The markedly increased gene and protein expression of arginase 1 already at admission indicates a role of arginase 1 in the development of STEMI.