Extensive serum biomarker analysis in patients with ST segment elevation myocardial infarction (STEMI)

The prediction value of platelet-derived growth factor for major adverse cardiovascular events in patients with acute non-ST-segment elevation myocardial infarction

BACKGROUND

The value of plasma Platelet-Derived Growth Factor (PDGF) as a biomarker in predicting major adverse cardiovascular events (MACEs) in patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) remains unclear.

METHODS

A total of 242 patients with NSTEMI were enrolled in this observational cohort study. The correlation between PDGF and MACEs was evaluated during a five-year follow-up. Kaplan-Meier survival analysis with Cox proportional-hazards regression was used to identify predictive values of PDGF.

RESULTS

The mean follow-up of NSTEMI patients was 1334 days. It was found that as the PDGF level increased, a significant uptrend in the incidence of MACEs and all-cause death, including the MACEs of 30 days, 180 days, 1 year, 5 years and the death of 1 year and 5 years (All Log-rank p < .05). Subgroup analysis further showed that PDGF had better predictive value for patients with age >65 years, GRACE score ≥140 and platelet count (PLT) >200 × 109/L.

CONCLUSION

PDGF levels can predict short-term and long-term MACEs in NSTEMI patients after discharge, especially for patients with older age, higher GRACE score and baseline PLT > 200 × 109/L.Key messagesPDGF is a risk factor for short- and long-term MACEs in patients with STEMI.PDGF has a better prognostic value in patients with older age and PLT > 200 × 109/L.Baseline plasma PDGF levels were positively correlated with GRACE score.

Bioinformatics analysis of potential common pathogenic mechanisms for systemic lupus erythematosus and acute myocardial infarction

BACKGROUND

Systemic lupus erythematosus (SLE) patients have a higher risk of acute myocardial infarction (AMI) compared to the general population. However, the underlying common mechanism of this association is not fully understood. This study aims to investigate the molecular mechanism of this complication.

METHODS

Gene expression profiles of SLE (GSE50772) and AMI (GSE66360) were obtained from the Gene Expression Omnibus (GEO) database. Common differentially expressed genes (DEGs) in SLE and AMI were identified, and functional annotation, protein-protein interaction (PPI) network analysis, module construction, and hub gene identification were performed. Additionally, transcription factor (TF)-gene regulatory network and TF-miRNA regulatory network were constructed for the hub genes.

RESULTS

70 common DEGs (7 downregulated genes and 63 upregulated genes) were identified and were mostly enriched in signaling pathways such as the IL-17 signaling pathway, TNF signaling pathway, lipid metabolism, and atherosclerosis. Using cytoHubba, 12 significant hub genes were identified, including IL1B, TNF, FOS, CXCL8, JUN, PTGS2, FN1, EGR1, CXCL1, DUSP1, MMP9, and ZFP36.

CONCLUSIONS

This study reveals a common pathogenesis of SLE and AMI and provides new perspectives for further mechanism research. The identified common pathways and hub genes may have important clinical implications for the prevention and treatment of AMI in SLE patients.

Neutrophil degranulation and myocardial infarction

Myocardial infarction (MI) is one of the most common cardiac emergencies with high morbidity and is a leading cause of death worldwide. Since MI could develop into a life-threatening emergency and could also seriously affect the life quality of patients, continuous efforts have been made to create an effective strategy to prevent the occurrence of MI and reduce MI-related mortality. Numerous studies have confirmed that neutrophils play important roles in inflammation and innate immunity, which provide the first line of defense against microorganisms by producing inflammatory cytokines and chemokines, releasing reactive oxygen species, and degranulating components of neutrophil cytoplasmic granules to kill pathogens. Recently, researchers reported that neutrophils are closely related to the severity and prognosis of patients with MI, and neutrophil to lymphocyte ratio in post-MI patients had predictive value for major adverse cardiac events. Neutrophils have been increasingly recognized to exert important functions in MI. Especially, granule proteins released by neutrophil degranulation after neutrophil activation have been suggested to involve in the process of MI. This article reviewed the current research progress of neutrophil granules in MI and discusses neutrophil degranulation associated diagnosis and treatment strategies.

Insulin-like growth factor binding protein-1 regulates HIF-1α degradation to inhibit apoptosis in hypoxic cardiomyocytes

Hypoxia is important in ischemic heart disease. Excessive Insulin-like growth factor binding protein-1 (IGFBP-1) amounts are considered to harm cardiomyocytes in acute myocardial infarction. However, the mechanisms by which IGFBP-1 affects cardiomyocytes remain undefined. The present study demonstrated that hypoxia up-regulates IGFBP-1 and HIF-1α protein expression in cardiomyocytes. Subsequent assays showed that IGFBP-1 suppression decreased HIF-1α expression and inhibited hypoxia-induced apoptosis in cardiomyocytes, which was reversed by HIF-1α overexpression, indicating that HIF-1α is essential to IGFBP-1 function in cellular apoptosis. In addition, we showed that IGFBP-1 regulated HIF-1α stabilization through interacting with VHL. The present findings suggest that IGFBP-1–HIF-1α could be targeted for treating ischemic heart disease.

Identification of Potential Biomarkers Associated with Acute Myocardial Infarction by Weighted Gene Coexpression Network Analysis

Background

In the general population, acute myocardial infarction (AMI) represents a significant cause of mortality. This study is aimed at identifying novel diagnostic biomarkers to aid in treating and diagnosing AMI.

Methods

The Gene Expression Omnibus (GEO) database was explored to extract two microarray datasets, GSE66360 and GSE48060, which were subsequently merged into a single cohort. Both AMI and control samples were analyzed for differentially expressed genes (DEGs), which were subsequently subjected to weighed gene coexpression network analysis (WGCNA) to identify the most significant module. Gene Ontology (GO) and pathway analyses subsequently carried out the most significant gene modules along with construction of a protein-protein interaction network (PPI). Cytoscape plugin cytoHubba allowed for the prediction of the top 4 key genes according to the network maximal clique centrality (MCC) algorithm. The expression levels and diagnostic value of the four key genes were additionally verified in the GSE62646 dataset.

Results

A WCGNA analysis revealed 878 DEGs which were clustered into 6 modules. The module with the most significance in AMI was colored blue. Subsequent GO and KEGG pathway enrichment analysis on blue module genes revealed that they were primarily enriched in the inflammation-related pathways. These findings, in combination with PPI and coexpression networks, resulted in the identification of the top four genes by cytoHubba, which included leukocyte immunoglobulin-like receptor B2 (LILRB2), toll-like receptor 2 (TLR2), neutrophil cytosolic factor 2 (NCF2), and S100A9. Among them, LILRB2, NCF2, and S100A9 were validated in the GSE62646 dataset.

Conclusions

The results suggested that LILRB2, NCF2, and S100A9 could be potential gene biomarkers for AMI.

An Integrative Review of Brain-Derived Neurotrophic Factor and Serious Cardiovascular Conditions

BACKGROUND

There is emerging evidence that supports a role for brain-derived neurotrophic factor (BDNF) in the risk and presence of serious cardiovascular conditions. However, few existing literature reviews methodically describe empirical findings regarding this relationship.

OBJECTIVES

The purpose of this integrative review was to (a) evaluate BDNF (serum/plasma BDNF levels, BDNF Val66Met genotype) among humans at risk for or with serious cardiovascular conditions and (b) investigate the relationship between BDNF and risk/presence of serious cardiovascular conditions in humans.

METHODS

An integrative review was conducted. Articles in English included human subjects, a measure of BDNF levels or BDNF gene, serious cardiovascular conditions, and quantitative data analyses. The search resulted in 475 unique titles, with the final sample including 35 articles representing 30 studies. Articles that received "good" or "fair" ratings (n = 31) using the National Heart, Lung, and Blood Institute Study Quality Assessment Tools were included for synthesis.

RESULTS

The retrieved articles were largely nonexperimental, with sample sizes ranging from 20 to 5,510 participants. Overall, BDNF levels were lower in patients with chronic heart failure and stroke, but higher in patients with unstable angina and recent myocardial infarction. Lower BDNF levels were associated with higher incidence of cardiovascular events in patients with a prior history of serious cardiovascular conditions and decreased cardiovascular risk in healthy samples. For BDNF genotype, on average, 36.3% of participants had Met alleles. The frequency of the BDNF Met allele varied across race/ethnicity and cardiovascular conditions and in terms of association with serious cardiovascular condition incidence/risk.

DISCUSSION

These findings indicate an emerging area of science. Future investigation is needed on serious cardiovascular condition phenotypes in relationship to BDNF in the same study conditions. Results also suggest for use of standardized BDNF measurement across studies and additional investigation in cardiovascular inflammatory processes that affect BDNF. Moreover, within specific populations, the frequency of Met alleles may be too low to be detected in sample sizes normally found in these types of studies.

Novel Biomarkers, ST-Elevation Resolution, and Clinical Outcomes Following Primary Percutaneous Coronary Intervention

Background Despite restoration of epicardial flow following primary percutaneous coronary intervention (PPCI), microvascular reperfusion as reflected by ST-elevation resolution (ST-ER) resolution remains variable and its pathophysiology remains unclear. Methods and Results Using principal component analyses, we explored associations between 91 serum biomarkers drawn before PPCI clustered into 14 pathobiologic processes (including NT-proBNP [N-terminal pro-B-type natriuretic peptide] as an independent cluster), and (1) ST-ER resolution ≥50% versus <50%; and (2) 90-day composite of death, shock, and heart failure. Network analyses were performed to understand interbiomarker relationships between the ST-ER groups. Among the 1160 patients studied, 861 (74%) had ST-ER ≥50% at a median 40 (interquartile range, 23-70) minutes following PPCI, yet both groups had comparable post-PPCI TIMI (Thrombolysis in Myocardial Infarction) grade 3 flow (86.6% versus 82.9%; P=0.25). ST-ER ≥50% was associated with significantly lower pre-PPCI concentrations of platelet activation cluster (particularly P-selectin, von Willebrand factor, and platelet-derived growth factor A) and NT-proBNP, including after risk adjustment. Across both ST-ER groups, strong interbiomarker relationships were noted between pathways indicative of myocardial stretch, platelet activation, and inflammation, whereas with ST-ER <50% correlations between iron homeostasis and inflammation were observed. Of all 14 biomarker clusters, only NT-proBNP was significantly associated with the 90-day clinical composite. Conclusions Suboptimal ST-ER is common despite achieving post-PPCI TIMI grade 3 flow. The cluster of platelet activation proteins and NT-proBNP were strongly correlated with suboptimal ST-ER and NT-proBNP was independently associated with 90-day outcomes. This analysis provides insights into the pathophysiology of microvascular reperfusion in ST-segment-elevation myocardial infarction and suggests novel pre-PPCI risk targets potentially amenable to enhancing tissue-level reperfusion following PPCI.

An exploratory analysis investigating blood protein biomarkers to augment ECG diagnosis of ACS

BACKGROUND

Acute Coronary Syndrome (ACS) is currently diagnosed using a 12‑lead Electrocardiogram (ECG). Our recent work however has shown that interpretation of the 12‑lead ECG is complex and that clinicians can be sub-optimal in their interpretation. Additionally, ECG does not always identify acute total occlusions in certain patients.

PURPOSE

The aim of the present study was to undertake an exploratory analysis to compare protein expression profiles of ACS patients that may in the future augment ECG diagnosis.

METHODS

Patients were recruited consecutively at the cardiac catheterization laboratory at Altnagelvin Hospital over a period of 6 months. A low risk control group was recruited by advertisement. Blood samples were analysed using the multiplex proximity extension assays by OLINK proteomics. Support vector machine (SVM) learning was used as a classifier to distinguish between patient groups on training data. The ST segment elevation level was extracted from each ECG for a subset of patients and combined with the protein markers. Quadratic SVM (QSVM) learning was then used as a classifier to distinguish STEMI from NSTEMI on training and test data.

RESULTS

Of the 344 participants recruited, 77 were initially diagnosed with NSTEMI, 7 with STEMI, and 81 were low risk controls. The other participants were those diagnosed with angina (stable and unstable) or non-cardiac patients. Of the 368 proteins analysed, 20 proteins together could significantly differentiate between patients with ACS and patients with stable angina (ROC-AUC = 0.96). Six proteins discriminated significantly between the stable angina and the low risk control groups (ROC-AUC = 1.0). Additionally, 16 proteins together perfectly discriminated between the STEMI and NSTEMI patients (ROC-AUC = 1). ECG comparisons with the protein biomarker data for a subset of patients (STEMI n = 6 and NSTEMI n = 6), demonstrated that 21 features (20 proteins + ST elevation) resulted in the highest classification accuracy 91.7% (ROC-AUC = 0.94). The 20 proteins without the ST elevation feature gave an accuracy of 80.6% (ROC-AUC 0.91), while the ST elevation feature without the protein biomarkers resulted in an accuracy of 69.3% (ROC-AUC = 0.81).

CONCLUSIONS

This preliminary study identifies panels of proteins that should be further explored in prospective studies as potential biomarkers that may augment ECG diagnosis and stratification of ACS. This work also highlights the importance for future studies to be designed to allow a comparison of blood biomarkers not only with ECG's but also with cardio angiograms.

Peripheral T cell receptor beta immune repertoire is promptly reconstituted after acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is characterized by an inflammatory process in which T cell plays a key role. However, the profile of immune microenvironment in AMI is still uncertain. High-throughput sequencing of T cell receptor (TCR) provides deep insight into monitoring the immune microenvironment.

METHODS

30 patients with AMI were enrolled and 30 healthy individuals were recruited as controls. Flow cytometer were used to analyze the distribution of αβ T cells and their CD69 expression from peripheral leukomonocytes. TCRβ repertoire library was amplified by two-round multiplex PCR and detected by next-generation sequencing (NGS).

RESULTS

The percentage of αβ T cells in AMI patients were significantly restricted than those in healthy controls, while the highly activated αβ T cells along with distinguishing usage of variable (V), diversity (D) and joining (J) gene segments were also found in AMI patients. In addition, AMI induced a significantly restricted CDR3 amino acid (AA) diversity and remarkably reconstituted TCR immune repertoires. Finally, we identified several AMI-associated tendency of CDR3 AAs expression after AMI.

CONCLUSIONS

Our work suggests that the aberrant αβ T cells distribution and activation may associated with the pathogenesis of AMI and demonstrates a reconstitution of TCRβ immune repertoire after AMI.

Important roles of the Ca2+-sensing receptor in vascular health and disease

Ca²⁺-sensing receptor (CaSR), a member of G protein-coupled receptor family, is widely expressed in the vascular system, including perivascular neurons, vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs). When stimulated, CaSR can further increase the cytosolic Ca²⁺ concentration ([Ca²⁺]_cyt) in two ways: intracellular Ca²⁺ release from endo/sarcoplasmic reticulum (ER/SR) and extracellular Ca²⁺ entry through Ca²⁺-permeable cation channels. In endothelium, increased Ca²⁺ subsequently activate nitric oxide synthase (NOS) and intermediate conductance Ca²⁺-activated K⁺ channels (IKCa), resulting in vasodilation through NOS-mediated NO release or membrane hyperpolarization. In VSMCs, CaSR-induced intracellular Ca²⁺ increase causes blood vessel constriction. CaSR activation predominantly induces vasorelaxation of whole vascular tissues through VECs-dependent mechanisms; however, CaSR-induced Ca²⁺ signaling in VSMCs may play a braking role in CaSR-mediated vasorelaxation. Emerging evidence reveals the importance of CaSR in the regulation of vascular tone and blood pressure. Here, we summarized recent advances in CaSR-mediated vascular reaction and the underlying mechanisms in different species, including humans. In addition, several studies have demonstrated that CaSR dysfunction may be associated with some fatal vascular diseases, such as pulmonary arterial hypertension, primary hypertension, diabetes, acute myocardial infarction and vascular calcification. With the advance of studies on CaSR in vascular health and disease, it is expected positive modulators or negative modulators of CaSR used for the treatment of specific diseases may be promising therapeutic options for the prevention and/or treatment of vascular diseases.

Differential gene expression profiles in peripheral blood in Northeast Chinese Han people with acute myocardial infarction

This study aimed to use gene chips to investigate differential gene expression profiles in the occurrence and development of acute myocardial infarction (AMI). The study included 12 AMI patients and 12 healthy individuals. Total mRNA of peripheral bloodwas extracted and reversed-transcribed to cDNA for microarray analysis. After establishing two pools with three subjects each (3 AMI patients and 3 healthy individuals), the remaining samples were used for RT-qPCR to confirm the microarray data. From the microarray results, seven genes were randomly selected for RT-qPCR. RT-qPCR results were analyzed by the 2^-ΔΔCt method. Microarray analysis showed that 228 genes were up- regulated and 271 were down-regulated (p ≤ 0.05, |logFC| > 1). Gene ontology showed that these genes belong to 128 cellular components, 521 biological processes, and 151 molecular functions. KEGG pathway analysis showed that these genes are involved in 107 gene pathways. RT-qPCR results for the seven genes showed expression levels consistent with those obtained by microarray. Thus, microarray data could be used to select the pathogenic genes for AMI. Investigating the abnormal expression of these differentially expressed genes might suggest efficient strategies for the prevention, diagnosis, and treatment of AMI.

Increased expression of angiogenic cytokines in CD56+ uterine natural killer cells from women with recurrent miscarriage

OBJECTIVE

To compare the expression pattern of angiogenic cytokines in CD56+ uNK cells from peri-implantation endometrium in women with a history of recurrent miscarriage and fertile controls.

METHODS

28 women were recruited, from which 18 women were diagnosed as recurrent miscarriage and 10 women were of proven fertility. Endometrial biopsy samples were obtained precisely 7 days after luteinization hormone surge in a natural cycle. The angiogenic profile of isolated CD56+ uNK cells was determined by RayBio human angiogenesis antibody array G Series 1000. Differentially expressed angiogenic cytokines between groups were validated by ELISA kits.

RESULTS

CD56+ uNK cells freshly isolated from peri-implantation endometrium were determined to be >90% pure. Angiogenic cytokine array demonstrated that CD56+ uNK cells are one of the angiogenic factors producers in endometrium around the time of embryo implantation. A differential angiogenic cytokine expression profile was found between two groups, with significantly higher expressions of angiogenin, VEGF-A and bFGF in CD56+ uNK cells from women with recurrent miscarriage, compared with fertile controls.

CONCLUSIONS

Differential angiogenic cytokine profile of isolated CD56+ uNK cells suggested the role of uNK cells in the altered endometrial vascularity at the time of implantation, which may account for the endometrial contribution to recurrent miscarriage.

High expression of long chain acyl-coenzyme A synthetase 1 in peripheral blood may be a molecular marker for assessing the risk of acute myocardial infarction

The current study aimed to investigate whether the increased expression of long chain acyl-coenzymeA synthetase 1 (ACSL1) in peripheral blood leukocytes (PBL) may be a molecular marker for the genetic evaluation of acute myocardial infarction (AMI). The mechanism of action of ACSL1 in the pathogenesis of AMI was also investigated. A total of 75 patients with AMI and 70 individuals without coronary heart disease were selected to participate in the present study. The demographic and clinical information of the enrolled subjects was recorded. Reverse transcription quantitative polymerase chain reaction and western blot analysis were applied to measure the expression of ACSL1 at the mRNA and protein levels. It was demonstrated that the expression of ACSL1 mRNA and protein in PBL was increased in patients with AMI compared with controls. Logistic regression analysis indicated that ACSL1 expression in PBL was an independent risk factor of AMI. There was a significant positive association between the level of ACSL1 expression and the degree of atherosclerosis in the coronary artery. Furthermore, patients with AMI exhibited an increased risk of atherosclerosis due to increased fasting blood glucose, total cholesterol, triglyceride and lipoprotein levels and decreased high-density lipoprotein levels, compared with controls. Therefore, the current study demonstrated that ACSL1 expression was increased in the PBLs of patients with AMI. The elevated expression of ACSL1 acts an independent risk factor of AMI and may act as a potential biomarker when determining the risk of AMI.

MMP Activity Detection in Zymograms

Matrix metalloproteinases (MMP) belong to a distinguished class of zinc-dependent endopeptidases. Zymography is a semi-quantitative tool for determining the activity of different MMP isoenzymes in a variety of biological samples. In substrate gel zymography, protein samples of different origin (tissue, cell lysates, plasma/serum, perfusates, other liquids) are separated in sodium dodecyl sulfate (SDS) polyacrylamide gels containing copolymerized substrate (gelatin, casein, elastin, etc.), and after incubation-enabling substrate cleavage by MMPs, MMP activities are detected after the gel staining as transparent bands against a dark-blue background. In situ zymography is a histological modification of substrate zymography in frozen sections, allowing detection of the localization of the MMP activities within the tissue. Here, we describe detailed experimental protocols of all abovementioned techniques and provide examples for several sample measurements.

Calcium-Sensing Receptor in Human Peripheral Blood T Lymphocytes Is Involved in the AMI Onset and Progression through the NF-κB Signaling Pathway

Acute myocardial infarction (AMI) is a condition triggered by an inflammatory process that seriously affects human health. Calcium-sensing receptor (CaSR) in T lymphocytes is involved during the inflammation reaction. However, the relationship between them is not very clear. In this study, we collected human peripheral blood T lymphocytes from patients with AMI and in different stages of percutaneous coronary intervention (PCI) (at the onset of AMI, the first day after PCI (PCI-1), PCI-3, and PCI-5) to study the CaSR and NF-κB pathway protein expression, cytokine release and T cell apoptosis. The results showed that the expressions of CaSR, P-p65, Caspase-12, and the secretions of Th-1 and Th-2 type cytokines were increased at the onset of AMI, especially on the PCI-1. Meanwhile, the apoptosis rate of CD(3+), CD(4+) and CD(8+) T lymphocytes also increased. However, from PCI-3, all the indicators began to decline. In addition, we also found that positive CaSR small interfering RNA (siRNA) transfection in T lymphocytes and NF-κB pathway blocker Bay-11-7082 reversed the increased expressions of CaSR, P-p65, Caspase-12, reduced the secretions of Th-1 and Th-2 type cytokines, and decreased T lymphocytes apoptosis rate not only in the AMI patients but also in the normal controls. All of these results indicated that CaSR in the human peripheral blood T lymphocytes were involved in the AMI onset and progression, which probably was related to the NF-κB pathway. Our study demonstrated the relationship between AMI and CaSR, and will provide new effective prevention theory and new targets for drug treatment.