Comparison of plasma microRNA-1 and cardiac troponin T in early diagnosis of patients with acute myocardial infarction

MicroRNAs: Midfielders of Cardiac Health, Disease and Treatment

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that play a role in post-transcriptional gene regulation. It is generally accepted that their main mechanism of action is the negative regulation of gene expression, through binding to specific regions in messenger RNA (mRNA) and repressing protein translation. By interrupting protein synthesis, miRNAs can effectively turn genes off and influence many basic processes in the body, such as developmental and apoptotic behaviours of cells and cardiac organogenesis. Their importance is highlighted by inhibiting or overexpressing certain miRNAs, which will be discussed in the context of coronary artery disease, atrial fibrillation, bradycardia, and heart failure. Dysregulated levels of miRNAs in the body can exacerbate or alleviate existing disease, and their omnipresence in the body makes them reliable as quantifiable markers of disease. This review aims to provide a summary of miRNAs as biomarkers and their interactions with targets that affect cardiac health, and intersperse it with current therapeutic knowledge. It intends to succinctly inform on these topics and guide readers toward more comprehensive works if they wish to explore further through a wide-ranging citation list.

Evolving Diagnostic and Management Advances in Coronary Heart Disease

Despite considerable improvement in diagnostic modalities and therapeutic options over the last few decades, the global burden of ischemic heart disease is steadily rising, remaining a major cause of death worldwide. Thus, new strategies are needed to lessen cardiovascular events. Researchers in different areas such as biotechnology and tissue engineering have developed novel therapeutic strategies such as stem cells, nanotechnology, and robotic surgery, among others (3D printing and drugs). In addition, advances in bioengineering have led to the emergence of new diagnostic and prognostic techniques, such as quantitative flow ratio (QFR), and biomarkers for atherosclerosis. In this review, we explore novel diagnostic invasive and noninvasive modalities that allow a more detailed characterization of coronary disease. We delve into new technological revascularization procedures and pharmacological agents that target several residual cardiovascular risks, including inflammatory, thrombotic, and metabolic pathways.

Up-Regulation of Cell-Free MicroRNA-1 and MicroRNA-221-3p Levels in Patients with Myocardial Infarction Undergoing Coronary Angiography

Purpose: Myocardial infarction (MI), known as a multifactorial disease, remains the predominant cause of mortality and sudden deaths annually. The current study aimed to measure the expression of microRNA-1 and microRNA-221-3p in MI patients.

Methods: In the current study, 100 healthy controls (with no history of heart disease) and 200 patients with MI were selected. Patients were divided into two groups based on angiography results: normal (no significant artery stenosis) and primary percutaneous coronary intervention (primary PCI, significant artery stenosis). The levels of microRNA-1 and microRNA-221-3p were quantified using real-time quantitative polymerase chain reaction. The correlation between levels of microRNAs and the common cardiac markers were analyzed statistically.

Results: In comparison to fold change, microRNA-1 elevations were 8.5-fold in normal patients and 60-fold in patients with primary PCI; while microRNA-221-3p levels were 210- fold higher in primary PCI and 31.31-fold higher in normal cases compared with the healthy controls. Receiver operating characteristic analysis showed that the area under the curve (AUC) for circulating microRNA-1 and microRNA-221 were 0.903 and 0.958 in normal patients and 0.927 and 0.985 in primary PCI patients (p < 0.0001), respectively. Pearson correlation (ρ) analysis showed that circulation of microRNA-1 correlated with serum levels of cardiac troponin I (CTnI) (ρ =0.24), creatinine (ρ =0.34), creatinine kinase-myocardial band (CK-MB) (ρ =0.31), and microRNA-221-3p was significantly correlated with serum levels of CTnI (ρ =0.6), creatinine (ρ =0.41), and CK-MB (ρ =0.37), (P < 0.0001).

Conclusion: The study underscored the potential of microRNA-1 and microRNA-221-3p as informative biomarkers and positively correlated with artery stenosis in MI.

A multiplexed ion-exchange membrane-based miRNA (MIX·miR) detection platform for rapid diagnosis of myocardial infarction

Micro RNAs (miRNAs) have shown great potential as rapid and discriminating biomarkers for acute myocardial infarction (AMI) diagnosis. We have developed a multiplexed ion-exchange membrane-based miRNA (MIX·miR) preconcentration/sensing amplification-free platform for quantifying in parallel a panel of miRNAs, including miR-1, miR-208b, and miR-499, from the same plasma samples from: 1) reference subjects with no evident coronary artery disease (NCAD); 2) subjects with stable coronary artery disease (CAD); and 3) subjects experiencing ST-elevation myocardial infarction (STEMI) prior to (STEMI-pre) and following (STEMI-PCI) percutaneous coronary intervention. The picomolar limit of detection from raw plasma and 3-decade dynamic range of MIX·miR permits detection of the miRNA panel in untreated samples from disease patients and its precise standard curve, provided by large 0.1 to 1 V signals and eliminates individual sensor calibration. The use of molecular concentration feature reduces the assay time to less than 30 minutes and increases the detection sensitivity by bringing all targets close to the sensors. miR-1 was low for NCAD patients but more than one order of magnitude above the normal value for all samples from three categories (CAD, STEMI-pre, and STEMI-PCI) of patients with CAD. In fact, miR-1 expression levels of stable CAD, STEMI-pre and STEMI-PCI are each more than 10-fold higher than the previous class, in that order, well above the 95% confidence level of MIX·miR. Its overexpression estimate is significantly higher than the PCR benchmark. This suggests that, in contrast to protein biomarkers of myocardial injury, miR-1 appears to differentiate ischemia from both reperfusion injury and non-AMI CAD patients. The battery-operated MIX·miR can be a portable and low-cost AMI diagnostic device, particularly useful in settings where cardiac catheterization is not readily available to determine the status of coronary reperfusion.

Exploring diagnostic and prognostic predictive values of microRNAs for acute myocardial infarction: A PRISMA-compliant systematic review and meta-analysis

OBJECTIVE

Previous investigations yielded inconsistent results for diagnostic and prognostic predictive values of MicroRNAs (miRNAs) for acute myocardial infarction (AMI).

METHODS AND RESULTS

We systematically searched on PubMed and Web of Science for articles explored association of miRNAs and AMI published from January 1989 to March 2019. For diagnostic studies, a summary of sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR), and diagnostic odds ratio (DOR), which indicated the accuracy of microRNAs in the differentiation of AMI and no AMI, were calculated from the true positive (TP), true negative (TN), false positive (FP), and false negative (FN) of each study. In addition, the summary receive-operating characteristics (SROC) curve was constructed to summarize the TP and FP rates. For follow-up study, we computed hazard ratios (HRs) and 95% confidence intervals (CIs) for individual clinical outcomes. The meta-analysis showed a sensitivity [0.72 (95% CI: 0.61--0.81)] and specificity [0.88 (95% CI: 0.79--0.94)] of miR-1 for AMI. In addition, miR-133 showed a sensitivity [0.73 (95% CI: 0.55--0.85)] and specificity [0.88 (95% CI: 0.74--0.95)] for AMI. Moreover, the present study showed a sensitivity [0.83 (95% CI: 0.74--0.89)] and specificity [0.96 (95% CI: 0.82--0.99)] of miR-208 for AMI. A significant association was found between miR-208 and mortality after AMI (HR 1.09, 95% CI 1.01--1.18). It also indicated a sensitivity [0.84 (95% CI: 0.70--0.92)] and specificity [0.97 (95% CI: 0.87--0.99)] of miR-499 for AMI.

CONCLUSIONS

Circulating miR-1, miR-133, miR-208, and miR-499 showed diagnostic values in AMI.

Comparison of the Clinical Value of miRNAs and Conventional Biomarkers in AMI: A Systematic Review

Background/Aims: This study aimed to compare the clinical value of the peak time point and area under the curve (AUC) of miRNAs and conventional biomarkers in acute myocardial infarction (AMI).

Methods: A literature search was carried out in PubMed, Web of Science, Embase, and Cochrane systematically. Screening studies, extracting data, and assessing article quality were performed independently by two researchers. Also, the names of miRNAs in the included studies were standardized by the miRBase database.

Results: A total of 40 studies, encompassing 6,960 participants, were included in this systematic review. The samples of circulating miRNAs were mainly from the plasma. The results of this systematic review displayed that miR-1-3p, miR-19b-3p, miR-22-5p, miR-122-5p, miR-124-3p, miR-133a/b, miR-134-5p, miR-150-5p, miR-186-5p, miR-208a, miR-223-3p, miR-483-5p, and miR-499a-5p reached peak time earlier and showed a shorter time window than the conventional biomarkers despite the different collection times of initial blood samples. miR-1-3p, miR-19b-3p, miR-133a/b, miR-208a/b, miR-223-3p, miR-483-5p, and miR-499a-5p were shown to be more valuable than classical biomarkers for the early diagnosis of AMI, and these miRNAs appeared to have the most potential biomarkers within 4 h of the onset of symptoms except miR-133a/b and miR-208b. Moreover, combined miRNAs or miRNAs combined with classical biomarkers could compensate for the deficiency of single miRNA and conventional biomarker in sensitivity or specificity for an optimal clinical value.

Conclusions: miR-1-3p, miR-19b-3p, miR-208a, miR-223-3p, miR-483-5p, and miR-499a-5p are promising biomarkers for AMI due to their satisfactory diagnostic accuracy and short time window (within 4 h of the onset of symptoms).

Cardiac Exosomes in Ischemic Heart Disease- A Narrative Review

Ischemic heart disease (IHD) is the primary cause of death globally. IHD is associated with the disruption of blood supply to the heart muscles, which often results in myocardial infarction (MI) that further may progress to heart failure (HF). Exosomes are a subgroup of extracellular vesicles that can be secreted by virtually all types of cells, including cardiomyocytes, cardiac fibroblasts, endothelial cells, and stem and progenitor cells. Exosomes represent an important means of cell–cell communication through the transport of proteins, coding and non-coding RNA, and other bioactive molecules. Several studies show that exosomes play an important role in the progression of IHD, including endothelial dysfunction, the development of arterial atherosclerosis, ischemic reperfusion injury, and HF development. Recently, promising data have been shown that designates exosomes as carriers of cardioprotective molecules that enhance the survival of recipient cells undergoing ischemia. In this review, we summarize the functional involvement of exosomes regarding IHD. We also highlight the cardioprotective effects of native and bioengineered exosomes to IHD, as well as the possibility of using exosomes as natural biomarkers of cardiovascular diseases. Lastly, we discuss the opportunities and challenges that need to be addressed before exosomes can be used in clinical applications.

Systematic review of microRNA biomarkers in acute coronary syndrome and stable coronary artery disease

The aim of this systematic review was to assess dysregulated miRNA biomarkers in coronary artery disease (CAD). Dysregulated microRNA (miRNAs) have been shown to be linked to cardiovascular pathologies including CAD and may have utility as diagnostic and prognostic biomarkers. We compared miRNAs identified in acute coronary syndrome (ACS) compared with stable CAD and control populations. We conducted a systematic search of controlled vocabulary and free text terms related to ACS, stable CAD and miRNA in Biosis Previews (OvidSP), The Cochrane Library (Wiley), Embase (OvidSP), Global Health (OvidSP), Medline (PubMed and OvidSP), Web of Science (Clarivate Analytics), and ClinicalTrials.gov which yielded 7370 articles. Of these, 140 original articles were appropriate for data extraction. The most frequently reported miRNAs in any CAD (miR-1, miR-133a, miR-208a/b, and miR-499) are expressed abundantly in the heart and play crucial roles in cardiac physiology. In studies comparing ACS cases with stable CAD patients, miR-21, miR-208a/b, miR-133a/b, miR-30 family, miR-19, and miR-20 were most frequently reported to be dysregulated in ACS. While a number of miRNAs feature consistently across studies in their expression in both ACS and stable CAD, when compared with controls, certain miRNAs were reported as biomarkers specifically in ACS (miR-499, miR-1, miR-133a/b, and miR-208a/b) and stable CAD (miR-215, miR-487a, and miR-502). Thus, miR-21, miR-133, and miR-499 appear to have the most potential as biomarkers to differentiate the diagnosis of ACS from stable CAD, especially miR-499 which showed a correlation between the level of their concentration gradient and myocardial damage. Although these miRNAs are potential diagnostic biomarkers, these findings should be interpreted with caution as the majority of studies conducted predefined candidate-driven assessments of a limited number of miRNAs (PROSPERO registration: CRD42017079744).

Value of Blood-Based microRNAs in the Diagnosis of Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Background: Recent studies have shown that blood-based miRNAs are dysregulated in patients with acute myocardial infarction (AMI) and are therefore a potential tool for the diagnosis of AMI. Therefore, this study summarized and evaluated studies focused on microRNAs as novel biomarkers for the diagnosis of AMI from the last ten years. Methods: MEDLINE, the Cochrane Central database, and EMBASE were searched between January 2010 and December 2019. Studies that assessed the diagnostic accuracy of circulating microRNAs in AMI were chosen. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve (AUC) were used to assess the test performance of miRNAs. Results: A total of 58 studies that included 8,206 participants assessed the diagnostic accuracy of circulating miRNAs in AMI. The main results of the meta-analyses are as follows: (1) Total miRNAs: the overall pooled sensitivity and specificity were 0.82 (95% CI: 0.79-0.85) and 0.87 (95% CI: 0.84-0.90), respectively. The AUC value was 0.91 (95% CI: 0.88-0.93) in the overall summary receiver operator characteristic (SROC) curve. (2) The panel of two miRNAs: sensitivity: 0.88 (95% CI: 0.77-0.94), specificity: 0.84 (95% CI: 0.72-0.91), AUC: 0.92 (95% CI: 0.90-0.94). (3) The panel of three miRNAs: sensitivity: 0.91 (95% CI: 0.85-0.94), specificity: 0.87 (95% CI: 0.77-0.92), AUC: 0.92 (95% CI: 0.89-0.94). (4) Results by types of miRNAs: miRNA-1: sensitivity: 0.78 (95% CI: 0.71-0.84), specificity: 0.86 (95% CI: 0.77-0.91), AUC: 0.88 (95% CI: 0.85-0.90); miRNA-133a: sensitivity: 0.85 (95% CI: 0.69-0.94), specificity: 0.92 (95% CI: 0.61-0.99), AUC: 0.93 (95% CI: 0.91-0.95); miRNA-208b: sensitivity: 0.80 (95% CI: 0.69-0.88), specificity: 0.96 (95% CI: 0.77-0.99), AUC: 0.91 (95% CI: 0.88-0.93); miRNA-499: sensitivity: 0.85 (95% CI: 0.77-0.91), specificity: 0.95 (95% CI: 0.89-0.98), AUC: 0.96 (95% CI: 0.94-0.97). Conclusion: miRNAs may be used as potential biomarkers for the detection of AMI. For single, stand-alone miRNAs, miRNA-499 may have better diagnostic accuracy compared to other miRNAs. We propose that a panel of multiple miRNAs with high sensitivity and specificity should be tested.

MicroRNA-186-5p serves as a diagnostic biomarker in atherosclerosis and regulates vascular smooth muscle cell proliferation and migration

Objective

MicroRNA dysregulation occurs in many human diseases, including atherosclerosis. Here, we examined the serum expression and clinical significance of miR-186-5p in patients with atherosclerosis, and explored its influence on vascular smooth muscle cell (VSMC) proliferation and migration.

Methods

Blood samples were collected from 104 patients with asymptomatic atherosclerosis and 80 healthy controls. Quantitative real-time PCR was applied to measure the miR-186-5p level. An ROC curve was established to assess the discriminatory ability of the serum miR-186-5p level for identifying atherosclerosis from controls. CCK-8 and Transwell assays were used to evaluate the impact of miR-186-5p on cell behaviors.

Results

Serum expression of miR-186-5p was significantly higher in atherosclerosis patients than in the control group. The serum miR-186-5p level showed a positive correlation with CIMT and could be used to distinguish atherosclerosis patients from healthy controls, with an area under the curve (AUC) score of 0.891. In VSMCs, overexpression of miR-186-5p significantly promoted cell proliferation and migration, while the opposite results were observed when miR-186-5p was downregulated.

Conclusion

Overexpression of miR-186-5p has a certain diagnostic significance for atherosclerosis. Upregulation of miR-186-5p stimulates VSMC proliferation and migration. Therefore, it is a possible target for atherosclerosis interventions.

Molecular miR-19a in Acute Myocardial Infarction: Novel Potential Indicators of Prognosis and Early Diagnosis

OBJECTIVE

Due to the increasing annual incidence rate of disability and mortality in patients with acute myocardial infarction (AMI), the need for an appropriate diagnostic tool has become a crucial urgent issue. An increase in biomarkers and protein levels in response to AMI can be used as a predictive biomarker with different sensitivities and specificities. This study aimed at investigating the role of miR-19a as a biomarker with acceptable sensitivity and specificity for early diagnosis of AMI.

METHODS

We studied 175 patients with AMI admitted within 12 h of symptom onset and 90 healthy subjects as control group. Patients were divided into two groups, including group I (normal vessels and no significant artery stenosis) and primary percutaneous coronary intervention (PCI) group II (patients with more than 50% stenosis in vessels and severe atherosclerosis) diagnosed by angiography. The expression level of miR-19a was evaluated by the real-time polymerase chain reaction and other serum chemistries were also analyzed.

RESULTS

The results demonstrated that circulating miR-19a levels were significantly increased in patient groups compared to the control group (2.88 ± 1.06 vs. 5.93 ± 1.28, P<0.0001). We also found that miR-19a levels were higher in group II (134.62-fold) than group I (15.42-fold). The upper levels of miR-19a were significantly correlated with the increased serum levels of CK-MB (ρ=0.29, P<0.0001), CTn I (ρ=0.4, P<0.0001) and creatinine (ρ=0.27, P<0.0001). In addition, Receiver Operating Characteristic (ROC) analysis revealed that circulating miR-19a had considerable diagnostic accuracy for the patients with normal vessel with an AUC of 0.930 (95% CI: 0.697-0.765) and for PCI patients with an AUC of 0.966 (95% CI: 0.748-0.784).

CONCLUSION

Circulating miR-19a possibly has prognostic value to be used as a promising molecular target for early diagnosis and prognosis of AMI.

Epigenetic Biomarkers in Cardiovascular Diseases

Cardiovascular diseases are the number one cause of death worldwide and greatly impact quality of life and medical costs. Enormous effort has been made in research to obtain new tools for efficient and quick diagnosis and predicting the prognosis of these diseases. Discoveries of epigenetic mechanisms have related several pathologies, including cardiovascular diseases, to epigenetic dysregulation. This has implications on disease progression and is the basis for new preventive strategies. Advances in methodology and big data analysis have identified novel mechanisms and targets involved in numerous diseases, allowing more individualized epigenetic maps for personalized diagnosis and treatment. This paves the way for what is called pharmacoepigenetics, which predicts the drug response and develops a tailored therapy based on differences in the epigenetic basis of each patient. Similarly, epigenetic biomarkers have emerged as a promising instrument for the consistent diagnosis and prognosis of cardiovascular diseases. Their good accessibility and feasible methods of detection make them suitable for use in clinical practice. However, multicenter studies with a large sample population are required to determine with certainty which epigenetic biomarkers are reliable for clinical routine. Therefore, this review focuses on current discoveries regarding epigenetic biomarkers and its controversy aiming to improve the diagnosis, prognosis, and therapy in cardiovascular patients.

Plasma MicroRNA as a novel diagnostic

MicroRNAs (miRNAs) are small, single-stranded, endogenous, non-coding RNAs necessary for proper gene expression. Their mechanism of action controls translation by base-pairing with target messenger RNA (mRNAs) thus leading to translation blockage or mRNA degradation. Many studies have shown that miRNAs play pivotal roles in cancer, cardiovascular disease and neurodegenerative disorders. The lack of blood-derived biomarkers and those markers of poor specificity and sensitivity significantly impact the ability to diagnose in general and at early disease stage specifically. As such, new, non-invasive and quantifiable biomarkers are needed. As post-transcriptional regulators of gene expression, miRNAs have been confirmed to be notably stable in cells, tissues and body fluids. These and other advantages make miRNAs ideal candidates as potential biomarkers and early experimental findings support this finding. This review examines the use of miRNAs as biomarkers in cancer, neurodegenerative, cardiovascular and liver disease and viral infection.

Circulating miR-182-5p and miR-5187-5p as biomarkers for the diagnosis of unprotected left main coronary artery disease

Background

Patients with unprotected left main coronary artery disease (uLMCAD) have high mortality rate due to sudden heart failure and acute myocardial infarction, for which reliable diagnostic biomarkers to detect this disease at an early stage are in urgent need. Circulating microRNAs (miRNAs) have emerged as a class of novel biomarkers for cardiovascular diseases. The purpose of this study was to investigate utility of miRNAs as biomarkers for early detection of uLMCAD.

Methods

High-throughput sequencing (NGS) was initially employed to compare circulating miRNA expression profiles in uLMCAD patients to that in patients without coronary artery disease (CAD) to identify candidate miRNA biomarkers. We further validated the expression of candidate miRNAs by quantitative polymerase chain reaction (qPCR) in a larger cohort. Receiver operating characteristic (ROC) analysis with multivariate logistic regression was used to evaluate the diagnostic power of candidate miRNAs individually and combined.

Results

MiR-182-5p, miR-199a-5p and miR-5187-5p were found significantly differentially expressed through NGS (fold changes =1.35, 1.65, 0.5, P values =0.018, 0.046, 0.030, respectively, n=5 for both uLMCAD group and non-CAD control group). In a larger cohort (n=27 for uLMCAD patient and n=38 for non-CAD controls), qPCR confirmed that expression of miR-182-5p was up-regulated (2.57-fold, P=0.011) and expression of miR-5187-5p was down-regulated (0.47-fold, P=0.018) in the plasma of uLMCAD patients. ROC analysis with multivariate logistic regression show that miR-182 and miR-5187 have an AUC score of 0.97 and 0.94 respectively, indicating high diagnostic power as biomarkers for uLMCAD. Interestingly, correlation analysis suggests that the expression of two miRNAs were independent to each other.

Conclusions

These results suggested that circulating miR-182-5p and miR-5187-5p were suitable diagnostic biomarkers for uLMCAD, both potentially providing diagnostic information for discriminating uLMCAD patients from non-CAD population prior to invasive diagnostic coronary angiography (CAG).

MiR-1/133 attenuates cardiomyocyte apoptosis and electrical remodeling in mice with viral myocarditis

BACKGROUND

The role of miR-1 and miR-133 in regulating the expression of potassium and calcium ion channels, and mediating cardiomyocyte apoptosis in mice with viral myocarditis (VMC) is investigated herein.

METHODS

Male Balb/c mice were randomly divided into groups: control group, VMC group, VMC + miR-1/133 mimics group, or VMC + miR-1/133 negative control (NC) group. VMC was induced with coxsackievirus B3 (CVB3). MiR-1/133 mimics ameliorated cardiac dysfunction in VMC mice and was compared to the VMC+NC group.

RESULTS

Hematoxylin and eosin staining showed a well-arranged myocardium without inflammatory cell infiltration in the myocardial matrix of the control group. However, in the VMC and VMC+NC groups, the myocardium was disorganized and swollen with necrosis, and the myocardial matrix was infiltrated with inflammatory cells. These changes were alleviated by miR-1/133 mimics. TUNEL staining revealed decreased cardiomyocyte apoptosis in the VMC + miR-1/133 mimics group compared with the VMC group. In addition, miR-1/133 mimics up-regulated the expression of miR-1 and miR-133, the potassium channel genes Kcnd2 and Kcnj2, as well as Bcl-2, and down-regulated the expression of the potassium channel suppressor gene Irx5, L-type calcium channel subunit gene a1c (Cacna1c), Bax, and caspase-9 in the myocardium of VMC mice. MiR-1/133 also up-regulated the protein levels of Kv4.2 and Kir2.1, and down-regulated the expression of CaV1.2 in the myocardium of VMC mice.

CONCLUSIONS

MiR-1 and miR-133 decreased cardiomyocyte apoptosis by mediating the expression of apoptosis-related genes in the hearts of VMC mice.

The diagnostic and prognostic value of circulating microRNAs in coronary artery disease: A novel approach to disease diagnosis of stable CAD and acute coronary syndrome

Coronary artery disease (CAD) is the most common manifestation of CVD and the acute coronary syndrome (ACS) is associated with a substantial morbidity and mortality in most populations globally. There are several biomarkers for diagnosis of MI. Troponin is routinely used as a biomarker in patients with chest pain, but it lacks sensitivity in the first hours of onset of symptoms, and so there is still a clinical need for new biomarkers for the diagnosis of CAD events. Recent studies have shown that miRNAs are involved in atherosclerotic plaque formation and their expression is altered during CAD events. Whilst studies have shown that several miRNAs are not superior to troponin in the diagnosis of a MI, they may be useful in the early diagnosis and prognosis of patients with CAD, however further studies are required. In this review we have summarized the recent studies investigating circulating miRNAs as novel biomarkers for the early detection of MI, CVD risk stratification and in the assessment of the prognosis of patients with ACS.

Identification of microRNAs as potential cellular monocytic biomarkers in the early phase of myocardial infarction: a pilot study

MicroRNA has been increasingly suggested to be involved in vascular inflammation. The aim of this study was to assess the expression profile of miRs as possible novel cellular biomarkers in circulating monocytes in patients with ST-segment elevation myocardial infarction (STEMI). Microarray techniques and TaqMan polymerase chain reaction were used to analyse the global expression of 352 miRNAs in peripheral blood monocytes from healthy donors (n = 20) and patients (n = 24) with acute STEMI. The expression level of miR-143 in monocytes from STEMI patients compared to healthy controls was increased, whereas the expression of miR-1, -92a, -99a, and -223 was reduced significantly. During 3.5 ± 1.5 months of follow-up miR-1 and -223 were back to baseline, whereas miR-92a and -99a return to normal levels over 3 months, but remained lower than healthy controls. Furthermore, monocytic expression of miR-143 was positively correlated with hs-CRP (R² = 0.338; P < 0.031), but not with cTnT. Importantly, treatment of monocytes isolated from healthy individuals with INFγ, but not LPS or TNFα caused an upregulation of miR-143 and downregulation of miR-1. Our findings identify circulating monocytes as putative biomarkers and as novel carriers for the cell-specific transfer of miRs in the early phase of myocardial infarction.

The diagnostic value of microRNA-4787-5p and microRNA-4306 in patients with acute aortic dissection

Acute aortic dissection (AAD) is a life-threatening cardiovascular disease with the high morbidity and mortality. Imaging modalities are the gold standard for the diagnosis of AAD; however, they are not always available in emergency department. Biomarker-assisted diagnosis is important for the early treatment of AAD. The aim of the present study was to identify potential microRNA (miRNA) biomarkers for AAD. Differentially expressed plasma miRNAs between AAD patients and age-matched healthy volunteers were analyzed by miRNA microarray. Quantitative RT-PCR was further performed to verify the expression of selected miRNAs (miR-4787-5p and miR-4306) with an increased number of samples. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of miR-4787-5p and miR-4306 as biomarkers for distinguishing AAD. Using TargetScan and miRanda, miR-4787-5p and miR-4306 were selected to predict target gene related to cytokines detecting by dual luciferase assay and western blotting. Nine upregulated and twelve downregulated miRNAs were identified in the circulating plasma of AAD patients. qRT-PCR verified statistically consistent expression of two selected miRNAs with microarray analysis. ROC analyses demonstrated that miR-4787-5p and miR-4306 were specific and sensitive for the early diagnosis of AAD. Bioinformatic predictions and dual luciferase assay suggested that polycystin-1 (PKD1) and transforming growth factor-β1 (TGF-β1) were respectively direct target of miR-4787-5p and miR-4306. Furthermore, the protein expression of the downstream targets of PKD1 and TGF-β1 were significantly reduced following overexpression of miR-4787-5p and miR-4306. These results revealed that miR-4787-5p and miR-4306 could be developed as diagnostic potential biomarkers for AAD, and they could be involved in the pathogenesis of AAD.

Identification of microRNAs as diagnostic biomarkers for acute myocardial infarction in Asian populations: A systematic review and meta-analysis

BACKGROUND

Acute myocardial infarction (AMI) is one of the leading causes of mortality and morbidity worldwide. Recently, several studies have revealed the diagnostic value of circulating microRNAs (miRNAs) for AMI detection. However, the diagnostic capacity of miRNAs for AMI is still controversial due to the inconsistent results among studies.

METHODS

A systematic literature search was conducted to retrieve relevant articles in PubMed and other databases up to February 2017. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were used to assess the overall test performance of miRNAs. Subgroup analysis was conducted to explore the potential sources of heterogeneity. We evaluated the publication bias by the Deeks' funnel plot asymmetry test and all statistical analyses were performed using Meta-disc 1.4 and Stata software.

RESULTS

A total of 26 articles comprising 1973 AMI patients and 1236 healthy controls were included in this meta-analysis. The overall pooled diagnostic data was as follows: the pooled sensitivity of 0.76 (95% confidence interval [CI]: 0.75-0.78), the pooled specificity of 0.82 (95% CI: 0.81-0.84), the pooled PLR of 4.68 (95% CI: 3.92-5.59), the pooled NLR of 0.28 (95% CI: 0.25-0.32), and the pooled DOR of 18.66 (95% CI: 14.11-24.68). The AUC value was 0.8661 in the overall summary receiver operator characteristic curve. Subgroup analysis indicated that miRNA-499 had better diagnostic accuracy over other miRNAs.

CONCLUSION

MiRNAs may serve as promising diagnostic biomarkers in the early diagnosis of AMI. Further studies were needed to evaluate the diagnostic value of miRNAs for AMI before clinical application.

Exosomal miRNAs in Heart Disease

Micro-RNAs (miRNAs) are small noncoding RNAs involved in the posttranscriptional regulation of gene expression. Exosomes have recently emerged as novel elements of intercellular communication in the cardiovascular system. Exosomal miRNAs could be key players in intercellular cross-talk, particularly during different diseases such as myocardial infarction (MI) and heart failure (HF). This review addresses the functional role played by exosomal miRNAs in heart disease and their potential use as new biomarkers.

Neutrophil-to-lymphocyte ratio in occlusive vascular diseases: the literature review of the past 10 years

BACKGROUND

This study aims to evaluate the results of studies investigating neutrophil-to-lymphocyte ratio (NLR) and to identify the prognostic and diagnostic value of NLR in occlusive vascular diseases.

METHODS

With the aim of identifying the studies related to NLR, a search was performed on http://www.ncbi.nlm.nih.gov/pubmed by using the key words "neutrophil lymphocyte ratio" between January 2005 and December 2014. All of the original articles were evaluated according to date of publications, countries, clinics and topics. Studies about occlusive vascular diseases were evaluated according to their qualifications, review methods and results. SPSS for Windows 16.0 was used in data analysis and data were expressed as mean, standard deviation and percentage.

RESULTS

A total of 735 original research articles were investigated. The number of publications have shown a regular logarithmic increase over the years. Thirty-two percent of all publications were performed by clinics in Turkey and 56.4% were performed by general-oncological surgery and cardiology clinics. A total of 107 publications were identified to be about occlusive vascular diseases, 80.3% of these publications were found to be prognostic and 19.6% to be diagnostic, 82.2% of them were found to be planned as retrospective and 17.7% as prospective. In 95.3% of prognostic publications, there was a positive correlation between high NLR values at admission and poor prognosis. In 95.3% of diagnostic publications high NLR values at admission were identified to be significant diagnostically.

CONCLUSION

Elevated neutrophil-to-lymphocyte ratio at admission, could be used as a diagnostic and/or prognostic parameter in occlusive vascular diseases.

Identifying circulating microRNAs as biomarkers of cardiovascular disease: a systematic review

The aim of the present study is to identify microRNAs (miRs) with high potential to be used as biomarkers in plasma and/or serum to clinically diagnose, or provide accurate prognosis for survival in, patients with atherosclerosis, coronary artery disease, and acute coronary syndrome (ACS). A systematic search of published original research yielded a total of 72 studies. After review of the risk of bias of the published studies, according to Cochrane Collaboration and the QUADUAS Group standards, 19 studies were selected. Overall 52 different miRs were reported. In particular, miR-133a/b (5 studies), miR-208a/b (6 studies), and miR-499 (7 studies) were well studied and found to be significant diagnostic and/or prognostic markers across different cardiovascular disease progression stages. miR-1 and miR-145b are potential biomarkers of ACS; miR-1 with higher sensitivity for all acute myocardial infarction (AMI), and miR-145 for STEMI and worse outcome of AMI. But when miRs were studied across different ACS study populations, patients had varying degrees of coronary stenosis, which was identified as an important confounder that limited the ability to quantitatively pool the study results. The identified miRs were found to regulate endothelial function and angiogenesis (miR-1, miR-133), vascular smooth muscle cell differentiation (miR-133, miR-145), communication between vascular smooth muscle and endothelial cell to stabilize plaques (miR-145), apoptosis (miR-1, miR-133, miR-499), cardiac myocyte differentiation (miR-1, miR-133, miR-145, miR-208, miR-499), and to repress cardiac hypertrophy (miR-133). Their role in these processes may be explained by regulation of shared RNA targets such as cyclin-dependent kinase inhibitor 1A (or p21), ETS proto-oncogene 1, fascin actin-bundling protein 1, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, insulin-like growth factor 1 receptor LIM and SH3 protein 1, purine nucleoside phosphorylase, and transgelin 2. These mechanistic data further support the clinical relevance of the identified miRs. miR-1, miR-133a/b, miR-145, miR-208a/b, and miR-499(a) in plasma and/or serum show some potential for diagnosis of cardiovascular disease. However, biased selection of miRs in most studies and unexplained contrasting results are major limitations of current miR research. Inconsistencies need to be addressed in order to definitively identify clinically useful miRs. Therefore, this paper presents important aspects to improve future miR research, including unbiased selection of miRs, standardization/normalization of reference miRs, adjustment for patient comorbidities and medication, and robust protocols of data-sharing plans that could prevent selective publication and selective reporting of miR research outcomes.

microRNA-based diagnostics and therapy in cardiovascular disease-Summing up the facts

Circulating microRNAs (miRNAs) are discussed as potential disease-specific biomarkers in cardiovascular disease. Their diagnostic value has been examined in numerous studies and animal models with respect to coronary artery disease (CAD) and myocardial infarction (MI) and the prognostic abilities of circulating miRNAs in risk stratification of future disease have been evaluated. Various miRNAs are described to complement protein-based biomarkers or classical risk factors in the diagnosis of CAD or MI and even represent potential new biomarkers in the discrimination of unstable angina pectoris (UAP). Signatures consisting of sets of multiple miRNAs seem to improve the predictive power compared to single miRNAs. Furthermore, the emerging field of miRNA-based therapeutics has reached cardiovascular research. The first promising in vitro results are raising hope for future clinical application. However, methods and material used for RNA isolation, miRNA detection and normalization steps still lack ways of standardization and need to be considered carefully. This article reviews the current knowledge of miRNAs in cardiovascular disease focusing on CAD and MI and will provide an overview regarding the use of circulating miRNAs as biomarkers and potential therapeutic targets in the field of CAD.