An extracellular vesicle epitope profile is associated with acute myocardial infarction

The current standard biomarker for myocardial infarction (MI) is high‐sensitive troponin. Although powerful in clinical setting, search for new markers is warranted as early diagnosis of MI is associated with improved outcomes. Extracellular vesicles (EVs) attracted considerable interest as new blood biomarkers. A training cohort used for diagnostic modelling included 30 patients with STEMI, 38 with stable angina (SA) and 30 matched‐controls. Extracellular vesicle concentration was assessed by nanoparticle tracking analysis. Extracellular vesicle surface‐epitopes were measured by flow cytometry. Diagnostic models were developed using machine learning algorithms and validated on an independent cohort of 80 patients. Serum EV concentration from STEMI patients was increased as compared to controls and SA. EV levels of CD62P, CD42a, CD41b, CD31 and CD40 increased in STEMI, and to a lesser extent in SA patients. An aggregate marker including EV concentration and CD62P/CD42a levels achieved non‐inferiority to troponin, discriminating STEMI from controls (AUC = 0.969). A random forest model based on EV biomarkers discriminated the two groups with 100% accuracy. EV markers and RF model confirmed high diagnostic performance at validation. In conclusion, patients with acute MI or SA exhibit characteristic EV biomarker profiles. EV biomarkers hold great potential as early markers for the management of patients with MI.     

Everolimus- and sirolimus-eluting stents in patients with and without ST-segment elevation myocardial infarction

Aims

Everolimus-eluting stents (EES) were superior to sirolimus-eluting stents (SES) in a dedicated myocardial infarction trial, a finding that was not observed in trials with low percentages of ST-elevation myocardial infarction (STEMI). Therefore, this study sought to investigate the influence of clinical presentation on outcome after EES and SES implantation.

Methods

A pooled population of 1602 randomised patients was formed from XAMI (acute MI trial) and APPENDIX-AMI (all-comer trial). Primary outcome was cardiac mortality, MI and target vessel revascularisation at 2 years. Secondary endpoints included definite/probable stent thrombosis (ST). Adjustment was done using Cox regression.

Results

In total, 902 EES and 700 SES patients were included, of which 44 % STEMI patients (EES 455; SES 257) and 56 % without STEMI (EES 447; SES 443). In the pooled population, EES and SES showed similar outcomes during follow-up. Moreover, no differences in the endpoints were observed after stratification according to presentation. Although a trend toward reduced early definite/probable ST was observed in EES compared with SES in STEMI patients, long-term ST rates were low and comparable.

Conclusions

EES and SES showed a similar outcome during 2-year follow-up, regardless of clinical presentation. Long-term safety was excellent for both devices, despite wide inclusion criteria and a large sub-population of STEMI patients.     

The nature of the problem: an overview of acute coronary syndromes and myocardial infarction

The leading cause of death worldwide is coronary heart disease (CHD). This often presents with atherosclerotic plaque rupture, leading to a partial or complete obstruction of coronary artery flow, and resulting ischemia or infarction of myocardial tissue. There are risk factors which can predict CHD risk, and the treatment of some risk factors can reduce the likelihood of developing an acute coronary syndrome (ACS). While the incidence of CHD may be decreasing in the developed world, significant increases are projected in the developing world. In addition to the immediate adverse events associated with ACS, these patients have long-term increases in morbidity and mortality, which make the worldwide epidemic of CHD a leading public health issue.     

Associations of serum high-sensitivity C-reactive protein and prealbumin with coronary vessels stenosis determined by coronary angiography and heart failure in patients with myocardial infarction

BackgroundTo explore the associations of serum high-sensitivity C-reactive protein (hs-CRP) and prealbumin (PAB) with the number of diseased coronary vessels, degree of stenosis and heart failure in patients with myocardial infarction (MI).MethodsA total of 39 MI patients treated in the Cardiology were selected as the observation group, and another 41 patients with normal results of coronary angiography during the same period were selected as the control group. The general data of patients were recorded in detail, the content of serum hs-CRP and PAB in the peripheral blood was detected, and the number of diseased coronary vessels and the degree of stenosis were detected via coronary angiography.ResultsCompared with those in control group, the blood pressure and heart rate significantly rose, the content of indexes related to the severity of MI were significantly increased, the content of hs-CRP was significantly increased, and the content of PAB was significantly decreased in observation group. Hs-CRP was positively correlated with the number of diseased coronary vessels, degree of stenosis and heart failure in patients, but PAB was negatively correlated with the above factors. The survival rate of MI patients with high content of hs-CRP was obviously lower than that of patients with low content of hsCRPConclusionsSerum hs-CRP and PAB are closely associated with the number of diseased coronary vessels, degree of stenosis and heart failure in MI patients.     

Time course studies on the initiation of complement activation in acute myocardial infarction induced by coronary artery ligation in rats

This study attempted to probe the role of complement activation in promoting acute myocardial infarction (AMI) induced by coronary artery ligation (CAL) in rats. The surgical technique used in this study significantly reduced early mortality (95% survival rate) and also reduced the variation in infarct size (33± 1.87%) at 32 h after surgery. Time course studies on the initiation of AMI at various time points were carried out using physiological, biochemical, histopathological and electron microscopical techniques. Serum markers and activities of lysosomal hydrolases were found to be significantly elevated at the 8th hour post ligation. Histological studies showed polymorphonuclear cells emigration and total coagulation necrosis. Transmission electron micrograph exhibited mild distortion of muscle fibres and mitochondrial rupture with disrupted cristae. Immunoblotting studies confirmed the presence of ₂-macroglobulin which supported the inflammatory response at 8th h of post ligation. The initiation of the complement (C) activation was observed by the increase in the level of the soluble form of the membrane attack complex (sC5b-9) in serum and left ventricle. Immunoexpression studies confirmed the initiation of the terminal C activation as shown by the expression of C5, C6, C7, C8, C9 and sC5b-9 complex at the 8th h of AMI. This study conclusively demonstrated that initiation of the C activation was observed to be significant at the 8th h of AMI induced by CAL in rats. (Mol Cell Biochem 268: 149–158, 2005)     

Brain endothelial barrier passage by monocytes is controlled by the endothelin system

Homeostasis of the brain is dependent on the blood-brain barrier (BBB). This barrier tightly regulates the exchange of essential nutrients and limits the free flow of immune cells into the CNS. Perturbations of BBB function and the loss of its immune quiescence are hallmarks of a variety of brain diseases, including multiple sclerosis (MS), vascular dementia, and stroke. In particular, diapedesis of monocytes and subsequent trafficking of monocyte-derived macrophages into the brain are key mediators of demyelination and axonal damage in MS. Endothelin-1 (ET-1) is considered as a potent pro-inflammatory peptide and has been implicated in the development of cardiovascular diseases. Here, we studied the role of different components of the endothelin system, i.e., ET-1, its type B receptor (ET(B)) and endothelin-converting enzyme-1 (ECE-1) in monocyte diapedesis of a human brain endothelial cell barrier. Our pharmacological inhibitory and specific gene knockdown studies point to a regulatory function of these proteins in transendothelial passage of monocytes. Results from this study suggest that the endothelin system is a putative target within the brain for anti-inflammatory treatment in neurological diseases.     

Identification of differentially expressed genes and the role of PDK4 in CD14+ monocytes of coronary artery disease

Background. Coronary artery disease (CAD) is a chronic inflammatory disease caused by development of atherosclerosis (AS), which is the leading cause of mortality and disability. Our study aimed to identify the differentially expressed genes (DEGs) in CD14⁺ monocytes from CAD patients compared with those from non-CAD controls, which might pave the way to diagnosis and treatment for CAD. Methods. The RNA-sequencing (RNA-seq) was performed by BGISEQ-500, followed by analyzing with R package to screening DEGs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed by R package. In addition, we validated the results of RNA-seq using real-time quantitative polymerase chain reaction (RT-qPCR). Furthermore, we explored the function of selected ten genes in LDL-treated CD14⁺ monocytes by RT-qPCR. Results. a total of 2897 DEGs were identified, including 753 up- and 2144 down-regulated genes in CD14⁺ monocytes from CAD patients. These DEGs were mainly enriched in plasma membrane and cell periphery of cell component, immune system process of biological process, NF-κB signaling pathway, cell adhesion molecules signaling pathway and cytokine–cytokine receptor interaction signaling pathway. In LDL-treated CD14⁺ monocytes, the mRNA expression of pyruvate dehydrogenase kinase 4 (PDK4) was significantly up-regulated. Conclusion. In the present study, we suggested that PDK4 might play a role in progression of CAD. The study will provide some pieces of evidence to investigate the role and mechanism of key genes in the pathogenesis of CAD.     

Big endothelin-1 level is a useful marker for predicting the presence of isolated coronary artery ectasia

Context: Endothelin-1(ET-1) has been implicated in coronary artery disease (CAD) and may be associated with coronary artery ectasia (CAE).

Objective: To clarify the relationship between big ET-1 and isolated CAE.

Methods: We measured big ET-1 with ELISA in 216 patients (CAE, n?=?72; CAD, n?=?72; normal, n?=?72) and evaluated the link with isolated CAE.

Results: The level of plasma big ET-1 was significantly higher in patients with isolated CAE (p?<?0.001). Big ET-1 was strongly and independently associated with CAE by multivariate analysis (OR 95%CI: 1.026 (1.018–1.034), p?=?0.000).

Conclusions: Big ET-1 may be a useful predictor for the presence of isolated CAE.     

ADRB2 polymorphisms predict the risk of myocardial infarction and coronary artery disease

Recently, the rs1042713 G > A and rs1042714 C > G polymorphisms in the beta-2adrenergic receptor (ADRB2) gene were shown to be related to atherosclerosisdiseases. Therefore, we performed a systemic meta-analysis to determine whether thetwo functional polymorphisms are related to the risk of myocardial infarction (MI)and coronary artery disease (CAD). We identified published studies that are relevantto our topic of interest. Seven case-control studies, with a total of 6,843 subjects,were incorporated into the current meta-analysis. Our analysis showed a higherfrequency of rs1042713 G > A variant in patients with MI or CAD compared tohealthy controls. A similar result was also obtained with the rs1042714 C > Gvariant under both the allele and dominant models. Ethnicity-stratified subgroupanalysis suggested that the rs1042714 C > G variant correlated with an increasedrisk of the two diseases in both Asians and Caucasians, while rs1042713 G > A onlycontributes to the risk of two diseases in Asians. In the disease type-stratifiedsubgroups, the frequencies of both the rs1042713 G > A and rs1042714 C > Gvariants were higher in the cases than in the controls in both the MI and CADsubgroups. Collectively, our data contribute towards understanding the correlationbetween the rs1042713 G > A and rs1042714 C > G polymorphisms inADRB2 and the susceptibility to MI and CAD.     

Extracellular ATP is a regulator of pathogen defence in plants

In healthy plants extracellular ATP (eATP) regulates the balance between cell viability and death. Here we show an unexpected critical regulatory role of eATP in disease resistance and defensive signalling. In tobacco, enzymatic depletion of eATP or competition with non-hydrolysable ATP analogues induced pathogenesis-related ( PR ) gene expression and enhanced resistance to tobacco mosaic virus and Pseudomonas syringae pv. tabaci . Artificially increasing eATP concentrations triggered a drop in levels of the important defensive signal chemical salicylic acid (SA) and compromised basal resistance to viral and bacterial infection. Inoculating tobacco leaf tissues with bacterial pathogens capable of activating PR gene expression triggered a rapid decline in eATP. Conversely, inoculations with mutant bacteria unable to induce defence gene expression failed to deplete eATP. Furthermore, a collapse in eATP concentration immediately preceded PR gene induction by SA. Our study reveals a previously unsuspected role for eATP as a negative regulator of defensive signal transduction and demonstrates its importance as a key signal integrating defence and cell viability in plants.     

Diabetes influences cardiac extracellular matrix remodelling after myocardial infarction and subsequent development of cardiac dysfunction

This study was conducted to examine the influence of acute streptozotocin‐induced diabetes on cardiac remodelling and function in mice subjected to myocardial infarction (MI) by coronary artery ligation. Echocardiography analysis indicated that diabetes induced deleterious cardiac functional changes as demonstrated by the negative differences of ejection fraction, fractional shortening, stroke volume, cardiac output and left ventricular volume 24 hrs after MI. Temporal analysis for up to 2 weeks after MI showed higher mortality in diabetic animals because of cardiac wall rupture. To examine extracellular matrix remodelling, we used fluorescent molecular tomography to conduct temporal studies and observed that total matrix metalloproteinase (MMP) activity in hearts was higher in diabetic animals at 7 and 14 days after MI, which correlated well with the degree of collagen deposition in the infarct area visualized by scanning electron microscopy. Gene arrays indicated temporal changes in expression of distinct MMP isoforms after 1 or 2 weeks after MI, particularly in diabetic mice. Temporal changes in cardiac performance were observed, with a trend of exaggerated dysfunction in diabetic mice up to 14 days after MI. Decreased radial and longitudinal systolic and diastolic strain rates were observed over 14 days after MI, and there was a trend towards altered strain rates in diabetic mouse hearts with dyssynchronous wall motion clearly evident. This correlated with increased collagen deposition in remote areas of these infarcted hearts indicated by Masson's trichrome staining. In summary, temporal changes in extracellular matrix remodelling correlated with exaggerated cardiac dysfunction in diabetic mice after MI.     

Thioredoxin-interacting protein promotes activation and inflammation of monocytes with DNA demethylation in coronary artery disease

Numerous studies have demonstrated that thioredoxin-interacting protein (TXNIP) expression of peripheral blood leucocytes is increased in coronary artery disease (CAD). However, the molecular mechanism of this phenomenon remained unclear. DNA methylation plays important roles in the regulation of gene expression. Therefore, we speculated there might be a close association between the expression of TXNIP and methylation. In this study, we found that compared with controls, DNA methylation at cg19693031 was decreased in CAD, while mRNA expressions of TXNIP and inflammatory factors, NLRP3, IL-1β, IL-18, were increased. Methylation at cg19693031 was negatively associated with TXNIP expression in the cohort, THP-1 and macrophages/foam cells. Furthermore, Transwell assay and co-cultured adhesion assay were performed to investigate functions of TXNIP on the migration of THP-1 or the adhesion of THP-1 on the surface of endothelial cells, respectively. Notably, overexpressed TXNIP promoted the migration and adhesion of THP-1 cells and expressions of NLRP3, IL-18 and IL-1β. Oppositely, knock-down TXNIP inhibited the migration and adhesion of THP-1 and expressions of NLRP3, IL-18. In conclusion, increased TXNIP expression, related to cg19693031 demethylation orientates monocytes towards an inflammatory status through the NLRP3 inflammasome pathway involved in the development of CAD.     

Oxidized LDL receptor gene (OLR1) is associated with the risk of myocardial infarction

Lectin-like oxidized low-density lipoprotein receptor (LOX-1/OLR1) has been suggested to play a role in the progression of atherogenesis. We analyzed the OLR1 gene and found a single nucleotide polymorphism (SNP), G501C, in patients with ischemic heart disease from a single family, which resulted in the missense mutation of K167N in LOX-1 protein. We compared the group of patients with myocardial infarction (MI) (n=102) with a group of clinically healthy subjects (n=102), and found that the MI group had a significantly high frequency of 501G/C+501C/C (38.2%) compared with the healthy group (17.6%; p<0.002). The odds ratio for the risk of MI associated with the 501G/C+501C/C genotype was 2.89 (95% CI, 1.51-5.53). These findings suggest that OLR1 or a neighboring gene linked with G501C SNP is important for the incidence of MI. Manipulating LOX-1 activity might be a useful therapeutic and preventative approach for coronary artery disease, especially for individuals with the G501C genotype of OLR1.     

Coronary artery bypass grafting is associated with immunoparalysis of monocytes and dendritic cells

Coronary artery bypass grafting (CABG) triggers a systemic inflammatory response that may contribute to adverse outcomes. Dendritic cells (DC) and monocytes are immunoregulatory cells potentially affected by CABG, contributing to an altered immune state. This study investigated changes in DC and monocyte responses in CABG patients at 5 time‐points: admission, peri‐operative, ICU, day 3 and day 5. Whole blood from 49 CABG patients was used in an ex vivo whole blood culture model to prospectively assess DC and monocyte responses. Lipopolysaccharide (LPS) was added in parallel to model responses to an infectious complication. Co‐stimulatory and adhesion molecule expression and intracellular mediator production was measured by flow cytometry. CABG modulated monocyte and DC responses. In addition, DC and monocytes were immunoparalysed, evidenced by failure of co‐stimulatory and adhesion molecules (eg HLA‐DR), and intracellular mediators (eg IL‐6) to respond to LPS stimulation. DC and monocyte modulation was associated with prolonged ICU length of stay and post‐operative atrial fibrillation. DC and monocyte cytokine production did not recover by day 5 post‐surgery. This study provides evidence that CABG modulates DC and monocyte responses. Using an ex vivo model to assess immune competency of CABG patients may help identify biomarkers to predict adverse outcomes.     

Serum Metrnl is associated with the presence and severity of coronary artery disease

Meteorin‐like (Metrnl) is a novel adipokine that is highly expressed in white adipose tissue. Metrnl stimulates energy expenditure and improves glucose tolerance in rodents. However, whether Metrnl plays a role in coronary artery disease (CAD) remains to be elucidated. The present study aimed to investigate the association of serum Metrnl with CAD in Chinese patients. A total of 193 patients with CAD and 156 control subjects were enrolled in this study. Serum Metrnl concentration was measured by enzyme‐linked immunosorbent assay. Anthropometric phenotypes, fasting glucose, serum lipids, and inflammatory cytokines were measured. Serum Metrnl was lower in CAD patients when compared to those controls (132.41 vs 173.17 pg/mL, P < 0.001). Serum Metrnl was negatively correlated with metabolic parameters, including body mass index, total cholesterol, and low‐density lipoprotein cholesterol as well as inflammatory markers including high‐sensitivity C‐reactive protein, IL‐1β, and IL‐11 even after adjustment for potential confounding variables (P < 0.05). In multivariable logistic regression analyses, compared to those in the highest tertile of serum Metrnl levels, subjects in the lowest tertile had the highest risks for CAD (adjusted OR = 2.63, 95% CI = 1.46‐4.27, P = 0.001). After adjustment for potential confounding variables, serum Metrnl was also decreased as the number of stenosed vessels increased (P < 0.001). Furthermore, decreased Metrnl level was negatively correlated with the severity of CAD quantified by the Gensini score. This first case‐control study shows significant associations of serum Metrnl with the presence and severity of CAD, suggesting Metrnl might be a new promising therapeutic target for CAD.     

Differential cytokine expression in myocytes and non-myocytes after myocardial infarction in rats

The proinflammatory cytokines interleukin (IL)-1 and IL-6 are increased after acute myocardial infarction (MI). Moreover, serum IL-6 level is elevated after MI, but has also been associated with heart failure. In the present study, heart function was monitored in a rat model of chronic MI. Cytokine expression in the infarcted and non-infarcted myocardium as well as in hearts of sham-operated controls was measured by the ribonuclease-protection assay. To identify the cells contributing to the increased cytokine expression, we further analyzed myocytes and non-myocytes isolated in the acute phase as well as during congestive heart failure (CHF) after MI. There was a strong induction in cytokine expression in the myocytes of the infarct area 6 h after MI. In the non-infarcted myocardium, cytokine expression increased only slightly in the non-myocytes after 6 h. This was not different from sham-operated controls and may, therefore, be induced by stress and catecholamines. In CHF, however, cytokine expression level in myocytes was normal. It increased slightly but significantly in the non-myocytes 4 and 8 weeks after MI. In conclusion, we suggest that pro-inflammatory cytokines, produced by the ischemic myocytes may be involved in the initiation of wound healing of the necrotic area, whereas the effect of pro-inflammatory cytokines in CHF, if any, seems not to be crucial.     

Effect of propranolol on cardiac cytokine expression after myocardial infarction in rats

The pro-inflammatory cytokines interleukin (IL)-1 and IL-6 have been shown to be upregulated in the myocardium after injury and after adrenergic receptor stimulation. Together with other cytokines, such as the transforming growth factor (TGF)-, the pro-inflammatory cytokines have been implicated in the initiation of tissue repair and wound healing after myocardial infarction (MI). In the present study, the effect of -adrenergic receptor blockade with propranolol (2 mg/kg·h s.c. by miniosmotic pumps) on cardiac cytokine expression and on wound healing was analyzed in rats from 6–72 h after MI. IL-1 and IL-6 gene expression strongly increased in the infarcted myocardium 6 h after MI and peaked after 12 h, while TGF-, progressively increased from 12 h onwards. Also, TGF-₂ increased after 12 h, peaked after 24 h and declined thereafter, while TGF-, was only elevated after 72 h. Treatment with propranolol had a negative chronotropic effect throughout the observation period of 72 h. It attenuated the initial elevation in LVEDP and increased cardiac output ultimately. Furthermore, propranolol attenuated IL-1 mRNA expression, but had not effect on the other cytokines. Moreover, MMP-9 gelatinolytic activity was markedly attenuated by propranolol indicating a delayed resorption of the necrotic tissue and, possibly, collagen turnover. Replacement by scar tissue, however, was not affected as indicated by normal collagen expression.     

Extracellular vesicles with ubiquitinated adenosine A2A receptor in plasma of patients with coronary artery disease

Extracellular vesicles (EV) can transfer cellular molecules for specific intercellular communication with potential relevance in pathological conditions. We searched for the presence in plasma from coronary artery disease (CAD) patients of EV containing the adenosine A_2A receptor (A_2AR), a signalling receptor associated with myocardial ischaemia and whose expression is related to homocysteine (HCy) metabolism. Using protein organic solvent precipitation for plasma EV preparation and Western blotting for protein identification, we found that plasma from CAD patients contained various amounts of EV with ubiquitin bound to A_2AR. Interestingly, the presence of ubiquitinated A_2AR in EV from patients was dependent on hyperhomocysteinemia, the amount being inversely proportional to A_2AR expression in peripheral mononuclear cells in patients with the highest levels of HCy. CEM, a human T cell line, was also found to released EV containing various amounts of ubiquitinated A_2AR in stimulated conditions depending on the hypoxic status and HCy level of culture medium. Together, these data show that ubiquitinated A_2AR‐containing EV circulate in the plasma of CAD patients and that this presence is related to hyperhomocysteinemia. A_2AR in plasma EV could be a useful tool for diagnosis and a promising drug for the treatment of CAD.