Plasma levels of microRNA-499 provide an early indication of perioperative myocardial infarction in coronary artery bypass graft patients

Small extracellular vesicles associated miRNA in myocardial fibrosis

Myocardial fibrosis involves the loss of cardiomyocytes, myocardial fibroblast proliferation, and a reduction in angiogenesis, ultimately leading to heart failure, Given its significant implications, it is crucial to explore novel therapies for myocardial fibrosis. Recently one emerging avenue has been the use of small extracellular vesicles (sEV)-carried miRNA. In this review, we summarize the regulatory role of sEV-carried miRNA in myocardial fibrosis. We explored not only the potential diagnostic value of circulating miRNA as biomarkers for heart disease but also the therapeutic implications of sEV-carried miRNA derived from various cellular sources and applications of modified sEV. This exploration is paramount for researchers striving to develop innovative, cell-free therapies as potential drug candidates for the management of myocardial fibrosis.

Identification of circulating microRNA-126-3p as a new biomarker for coronary artery calcification

Objective

Several circulating microRNAs, including microRNA-126-3p, have been identified as diagnostic and prognostic biomarker of cardiovascular disease. However, whether microRNA-126-3p is an independent risk predictor for coronary artery calcification is unclear.

Methods

In this prospective single-center study, we collected blood samples from coronary artery atherosclerosis patients (n = 54), patients with coronary artery calcification (n = 33) and controls (n = 56). Total RNA was extracted from plasma and blood cells with TRIzol reagents. The microRNA-126-3p level was determined via quantitative real-time polymerase chain reaction (RT-PCR).

Results

MicroRNA-126-3p levels were significantly increased in patients with coronary artery calcification than in coronary artery atherosclerosis patients or controls. The highest expression of microRNA-126-3p was observed in patients with moderate calcification who were diagnosed with Grade 2 calcification by coronary angiography. Age, microRNA-126-3p expression in veins, hypertension and diabetes significantly influence the occurrence of coronary artery calcification, among which diabetes and venous microRNA-126-3p expression were found to be independent risk factors for coronary artery calcification.

Conclusions

Taken together, the data in this study suggest that circulating microRNA-126-3p may be a novel noninvasive biomarker for coronary artery calcification. Regulating microRNA-126-3p expression may be an effective and promising strategy for the diagnosis and treatment of cardiovascular diseases, especially coronary artery calcification.

Differential gene expression patterns in ST-elevation Myocardial Infarction and Non-ST-elevation Myocardial Infarction

The ST-elevation Myocardial Infarction (STEMI) and Non-ST-elevation Myocardial Infarction (NSTEMI) might occur because of coronary artery stenosis. The gene biomarkers apply to the clinical diagnosis and therapeutic decisions in Myocardial Infarction. The aim of this study was to introduce, enrich and estimate timely the blood gene profiles based on the high-throughput data for the molecular distinction of STEMI and NSTEMI. The text mining data (50 genes) annotated with DisGeNET data (144 genes) were merged with the GEO gene expression data (5 datasets) using R software. Then, the STEMI and NSTEMI networks were primarily created using the STRING server, and improved using the Cytoscape software. The high-score genes were enriched using the KEGG signaling pathways and Gene Ontology (GO). Furthermore, the genes were categorized to determine the NSTEMI and STEMI gene profiles. The time cut-off points were identified statistically by monitoring the gene profiles up to 30 days after Myocardial Infarction (MI). The gene heatmaps were clearly created for the STEMI (high-fold genes 69, low-fold genes 45) and NSTEMI (high-fold genes 68, low-fold genes 36). The STEMI and NSTEMI networks suggested the high-score gene profiles. Furthermore, the gene enrichment suggested the different biological conditions for STEMI and NSTEMI. The time cut-off points for the NSTEMI (4 genes) and STEMI (13 genes) gene profiles were established up to three days after Myocardial Infarction. The study showed the different pathophysiologic conditions for STEMI and NSTEMI. Furthermore, the high-score gene profiles are suggested to measure up to 3 days after MI to distinguish the STEMI and NSTEMI.

A circulating miR-19b-based model in diagnosis of human breast cancer

Abstract Objective: Breast cancer (BC) is becoming the leading cause of cancer-related death in women all over the word. Identification of diagnostic biomarkers for early detection of BC is one of the most effective ways to reduce the mortality.

Methods: Plasma samples from BC patients (n = 120) and normal controls (n = 50) were collected to determine the differentially expressed circulating miRNAs in BC patients. Binary logistic regression was applied to develop miRNA diagnostic models. Receiver operating characteristic (ROC) curves were applied to calculate the area under the curve (AUC). MMTV-PYMT mammary tumor mice were used to validate the expression change of those circulating miRNAs. Plasma samples from patients with other tumor types were collected to determine the specificity of the model in diagnosis of BC.

Results: In the screening phase, 5 circulating miRNAs (miR-16, miR-17, miR-19b, miR-27a, and miR-106a) were identified as the most significantly upregulated miRNAs in plasma of BC patients. In consistence, the 5 miRNAs showed upregulation in the circulation of additional 80 BC patients in a tumor stage-dependent manner. Application of a tumor-burden mice model further confirmed upregulation of the 5 miRNAs in circulation. Based on these data, five models with diagnostic potential of BC were developed. Among the 5 miRNAs, miR-19b ranked at the top position with the highest specificity and the biggest contribution. In combination with miR-16 and miR-106a, a miR-19b-based 3-circulating miRNA model was selected as the best for further validation. Taken the samples together, the model showed 92% of sensitivity and 90% of specificity in diagnosis of BC. In addition, three other tumor types including prostate cancer, thyroid cancer and colorectal cancer further verified the specificity of the BC diagnostic model. Conclusion: The current study developed a miR-19b-based 3-miRNA model holding potential for diagnosis of BC using blood samples.

microRNA Expression Levels Change in Neonatal Patients During and After Exposure to Cardiopulmonary Bypass

Background The systemic inflammation that occurs after exposure to cardiopulmonary bypass (CPB), which is especially severe in neonatal patients, is associated with poorer outcomes and is not well understood. In order to gain deeper insight into how exposure to bypass activates inflammatory responses in circulating leukocytes, we studied changes in microRNA (miRNA) expression during and after exposure to bypass. miRNAs are small noncoding RNAs that have important roles in modulating protein levels and function of cells. Methods and Results We performed miRNA-sequencing on leukocytes isolated from neonatal patients with CPB (n=5) at 7 time points during the process of CPB, including before the initiation of bypass, during bypass, and at 3 time points during the first 24 hours after weaning from bypass. We identified significant differentially expressed miRNAs using generalized linear regression models, and miRNAs were defined as statistically significant using a false discovery rate-adjusted P<0.05. We identified gene targets of these miRNAs using the TargetScan database and identified significantly enriched biological pathways for these gene targets. We identified 54 miRNAs with differential expression during and after CPB. These miRNAs clustered into 3 groups, including miRNAs that were increased during and after CPB (3 miRNAs), miRNAs that decreased during and after CPB (10 miRNAs), and miRNAs that decreased during CPB but then increased 8 to 24 hours after CPB. A total of 38.9% of the target genes of these miRNAs were significantly differentially expressed in our previous study. miRNAs with altered expression levels are predicted to significantly modulate pathways related to inflammation and signal transduction. Conclusions The unbiased profiling of the miRNA changes that occur in the circulating leukocytes of patients with bypass provides deeper insight into the mechanisms that underpin the systemic inflammatory response that occurs in patients after exposure to CPB. These data will help the development of novel treatments and biomarkers for bypass-associated inflammation.

Diagnostic potential of a circulating miRNA model associated with therapeutic effect in heart failure

Heart failure (HF), as the leading cause of death, is continuing to increase along with the aging of the general population all over the world. Identification of diagnostic biomarkers for early detection of HF is considered as the most effective way to reduce the risk and mortality. Herein, we collected plasma samples from HF patients (n = 40) before and after medical therapy to determine the change of circulating miRNAs through a quantitative real-time PCR (QRT-PCR)-based miRNA screening analysis. miR-30a-5p and miR-654-5p were identified as the most significantly changed miRNAs in the plasma of patients upon treatment. In consistence, miR-30a-5p showed upregulation and miR-654-5p showed downregulation in the circulation of 30 HF patients, compared to 15 normal controls in the training phase, from which a two-circulating miRNA model was developed for HF diagnosis. Next, we performed the model validation using an independent cohort including 50 HF patients and 30 controls. As high as 98.75% of sensitivity and 95.00% of specificity were achieved. A comparison between the miRNA model and NT-pro BNP in diagnostic accuracy of HF indicated an upward trend of the miRNA model. Moreover, change of the two miRNAs was further verified in association with the therapeutic effect of HF patients, in which miR-30a-5p showed decrease while miR-654-5p showed increase in the plasma of patients after LVAD implantation. In conclusion, the current study not only identified circulating miR-654-5p for the first time as a novel biomarker of HF, but also developed a novel 2-circulating miRNA model with promising potentials for diagnosis and prognosis of HF patients, and in association with therapeutic effects as well.

Functional Role of microRNAs in Regulating Cardiomyocyte Death

microRNAs (miRNA, miRs) play crucial roles in cardiovascular disease regulating numerous processes, including inflammation, cell proliferation, angiogenesis, and cell death. Herein, we present an updated and comprehensive overview of the functional involvement of miRs in the regulation of cardiomyocyte death, a central event in acute myocardial infarction, ischemia/reperfusion, and heart failure. Specifically, in this systematic review we are focusing on necrosis, apoptosis, and autophagy.

Diagnostic and Prognostic Value of miRNAs after Coronary Artery Bypass Grafting: A Review

MiRNAs are noncoding, 21-24 nucleotide-long RNA particles that control over 60% of genes. MiRNAs affect gene expression through binding to the 3'-untranslated region of messenger RNA (mRNA), thus inhibiting mRNA translation or inducing mRNA degradation. MiRNAs have been associated with various cardiovascular diseases, including heart failure, hypertension, left ventricular hypertrophy, or ischemic heart disease. In addition, miRNA expression alters during coronary artery bypass grafting (CABG) surgery, which could be used to predict perioperative outcomes. CABG is an operation in which complex coronary arteries stenosis is treated by bypassing atherosclerotic lesions with venous or arterial grafts. Despite a very low perioperative mortality rate and excellent long-term survival, CABG is associated with postoperative complications, including reperfusion injury, graft failure, atrial fibrillation and perioperative myocardial infarction. So far, no reliable diagnostic and prognostic tools to predict prognosis after CABG have been developed. Changes in the perioperative miRNA expression levels could improve the diagnosis of post-CABG myocardial infarction and atrial fibrillation and could be used to stratify risk after CABG. Herein, we describe the expression changes of different subtypes of miRNAs during CABG and review the diagnostic and prognostic utility of miRNAs in patients undergoing CABG.

Aberrant DNA methylation and miRNAs in coronary artery diseases and stroke: a systematic review

Coronary artery disease (CAD) and ischemic stroke are the two most predominant forms of cardiovascular diseases (CVDs) caused by genetic, epigenetic and environmental risk factors. Although studies on the impact of 'epigenetics' in CVDs is not new, its effects are increasingly being realized as a key regulatory determinant that may drive predisposition, pathophysiology and therapeutic outcome. The most widely studied epigenetic risk factors are regulated by DNA methylation and miRNA expression. To keep pace with growing developments and discoveries, a comprehensive review was performed using Pubmed, Science Direct and Scopus databases to highlight the role of DNA methylation and miRNAs in CAD and stroke subjects. Network analysis was performed using ClueGO software and miRTargetLink database. We identified 32 studies of DNA methylation on CAD and stroke, of which, 6 studies showed differences in global DNA methylation, 10 studies reported the genome-wide difference in DNA methylation and 16 studies demonstrated altered DNA methylation at 14 candidate loci. The network analysis showed positive regulation of nitric oxide biosynthetic process, homocysteine metabolic process and negative regulation of lipid storage. About, 155 miRNAs were associated with CAD, stroke and related phenotypes in 83 studies. Interestingly, mir-223 hypomethylation and altered expression were associated with cerebral infarction and stroke. The target prediction for 18 common miRNAs between CAD and stroke showed strong interaction with SP3 and SP1 genes. This systematic review addresses the present knowledge on DNA methylation and miRNAs in CAD and stroke, whose abnormal regulation has been implicated in etiology or progression of the diseases.

Circulating MicroRNAs: Biogenesis and Clinical Significance in Acute Myocardial Infarction

Acute myocardial infarction (AMI) causes many deaths around the world. Early diagnosis can prevent the development of AMI and provide theoretical support for the subsequent treatment. miRNAs participate in the AMI pathological processes. We aim to determine the early diagnostic and the prognostic roles of circulating miRNAs in AMI in the existing studies and summarize all the data to provide a greater understanding of their utility for clinical application. We reviewed current knowledge focused on the AMI development and circulating miRNA formation. Meanwhile, we collected and analyzed the potential roles of circulating miRNAs in AMI diagnosis, prognosis and therapeutic strategies. Additionally, we elaborated on the challenges and clinical perspectives of the application of circulating miRNAs in AMI diagnosis. Circulating miRNAs are stable in the circulation and have earlier increases of circulating levels than diagnostic golden criteria. In addition, they are tissue and disease-specific. All these characteristics indicate that circulating miRNAs are promising biomarkers for the early diagnosis of AMI. Although there are several limitations to be resolved before clinical use, the application of circulating miRNAs shows great potential in the early diagnosis and the prognosis of AMI.

Diagnostic dilemma of perioperative myocardial infarction after coronary artery bypass grafting: A review

Coronary artery bypass grafting (CABG) is one of the most commonly performed cardiac procedures in the United States (US) and Europe. In the US, perioperative morbidity and mortality related to CABG are below 5%. One of the most significant complications following CABG, however, is perioperative myocardial infarction (PMI). Cardiac biomarkers, intra- and post-operative echocardiography, and electrocardiography are routinely used to monitor for evidence of PMI. In this review, we seek to summarize how each of these modalities is used in the clinical setting to differentiate PMI from expected procedure-related changes, and how these findings impact patients' outcomes. We conclude that while no perfect diagnostic test for the detection of clinically meaningful PMI exists, using a combination of existing modalities with knowledge of expected post-procedure changes allows for early and reliable detection. Future development is needed to create more sensitive and specific modalities for the detection of PMI in patients undergoing CABG.

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.

Circulatory miR-133b and miR-21 as Novel Biomarkers in Early Prediction and Diagnosis of Coronary Artery Disease

While coronary artery disease (CAD) has become a major threat worldwide, the timely biomarker-based early diagnosis of CAD remains a major unmet clinical challenge. We aimed towards assessing the level of circulatory microRNAs as candidates of novel biomarkers in patients with CAD. A total of 147 subjects were recruited which includes 78 subjects with angiographically proven CAD, 15 pre-atherosclerotic normal coronary artery (NCA) subjects and 54 healthy individuals. Quantitative real-time PCR assays were performed. MiR-133b was downregulated by 4.6 fold (p < 0.0001) whereas miR-21 was upregulated by ~2 fold (p < 0.0001) in plasma samples of CAD patients. Importantly, both the miRNAs showed association with disease severity as miR-133b was downregulated by 8.45 fold in acute coronary syndrome (ACS), 3.38 fold in Stable angina (SA) and 2.08 fold in NCA. MiR-21 was upregulated by 2.46 fold in ACS, 1.90 fold in SA and 1.12 fold in NCA. Moreover, miR-133b could significantly differentiate subjects with ST-elevation myocardial infarction (STEMI) from Non-STEMI. Area under the curve (AUC) for miR-133b was 0.80 with >75.6% sensitivity and specificity, AUC for miR-21 was 0.79 with >69.4% sensitivity and specificity. Our results suggest that miR-133b and miR-21 could be possible candidates of novel biomarkers in early prediction of CAD.

MicroRNA and Cardiovascular Diseases

Cardiovascular diseases are one of the most common causes of death in both developing and developed countries worldwide. Even though there have been improvements in primary prevention, the prevalence of cardiovascular diseases continues to increase in recent years. Hence, it is crucial to both investigate the molecular pathophysiology of cardiovascular diseases in-depth and find novel biomarkers regarding the early and proper prevention and diagnosis of these diseases. MicroRNAs, or miRNAs, are endogenous, conserved, single-stranded non-coding RNAs of 21-25 nucleotides in length. miRNAs have important roles in various cellular events such as embryogenesis, proliferation, vasculogenesis, apoptosis, cell growth, differentiation, and tumorigenesis. They also have potential roles in the cardiovascular system, including angiogenesis, cardiac cell contractility, control of lipid metabolism, plaque formation, the arrangement of cardiac rhythm, and cardiac cell growth. Circulating miRNAs are promising novel biomarkers for purposes of the diagnosis and prognosis of cardiovascular diseases. Cell or tissue specificity, stability in serum or plasma, resistance to degradative factors such as freeze-thaw cycles or enzymes in the blood, and fast-release kinetics, provide the potential for miRNAs to be surrogate markers for the early and accurate diagnosis of disease and for predicting middle- or long-term prognosis. Moreover, it may be a logical approach to combine miRNAs with traditional biomarkers to improve risk stratification and long-term prognosis. In addition to their efficacy in both diagnosis and prognosis, miRNA-based therapeutics may be beneficial for treating cardiovascular diseases using novel platforms and computational tools and in combination with traditional methods of analysis. microRNAs are promising, novel therapeutic agents, which can affect multiple genes using different signaling pathways. miRNAs therapeutic modulation techniques have been used in the settings of atherosclerosis, acute myocardial infarction, restenosis, vascular remodeling, arrhythmias, hypertrophy and fibrosis, angiogenesis and cardiogenesis, aortic aneurysm, pulmonary hypertension, and ischemic injury. This review presents detailed information about miRNAs regarding structure and biogenesis, stages of synthesis and functions, expression profiles in serum/plasma of living organisms, diagnostic and prognostic potential as novel biomarkers, and therapeutic applications in various diseases.

Plasma Levels of Myocardial MicroRNA-133a Increase by Intraoperative Cytokine Hemoadsorption in the Complex Cardiovascular Operation

Background

Complex cardiovascular procedures may initiate a systemic inflammatory response syndrome (SIRS) with a massive cytokine release, which is involved in postoperative myocardial injury. Intraoperative cytokine hemoadsorption (HA) mitigates the inflammatory response. Micro ribonucleic acids (miRNAs) are emerging as a marker of myocardial injury.

Methods

This study evaluated if intraoperative cytokine reduction by HA modulates SIRS and affects myocardial injury as measured by miRNA-126, 223 and miRNA-1, 133a, respectively. Twenty-eight patients were assigned into HA (n = 15) and control (C) (n = 13) groups. HA was performed by integrating CytoSorb™ into the extracorporeal circuit.

Results

MiRNA-133a plasma levels were increased postoperatively in both groups but were much higher in the HA group than in the C group at 3 h (P = 0.037) and 18 h (P = 0.017) after reperfusion. MiRNA-1 and miRNA-223 plasma levels were significantly increased postoperatively, but did not differ between groups. The vascular miRNA-126 was not affected.

Conclusion

Intraoperative cytokine HA in cardiovascular operations increased the plasma levels of miRNA-133a, suggesting higher myocardial injury.

Extracellular Vesicles in Cardiovascular Diseases: Alternative Biomarker Sources, Therapeutic Agents, and Drug Delivery Carriers

Cardiovascular diseases (CVD) represent the leading cause of morbidity and mortality globally. The emerging role of extracellular vesicles (EVs) in intercellular communication has stimulated renewed interest in exploring the potential application of EVs as tools for diagnosis, prognosis, and therapy in CVD. The ubiquitous nature of EVs in biological fluids presents a technological advantage compared to current diagnostic tools by virtue of their notable stability. EV contents, such as proteins and microRNAs, represent specific signatures of cellular activation or injury. This feature positions EVs as an alternative source of biomarkers. Furthermore, their intrinsic activity and immunomodulatory properties offer EVs unique opportunities to act as therapeutic agents per se or to serve as drug delivery carriers by acting as miniaturized vehicles incorporating bioactive molecules. In this article, we aim to review the recent advances and applications of EV-based biomarkers and therapeutics. In addition, the potential of EVs as a drug delivery and theranostic platform for CVD will also be discussed.

MiRNA-208a as a Sensitive Early Biomarker for the Postoperative Course Following Congenital Heart Defect Surgery

Current clinical risk assessment strategies have poor accuracy for identifying patients who will suffer adverse perioperative events. There is an ongoing need to integrate clinical variables with novel technology and biomarkers to accurately predict outcome after pediatric heart surgery. We tested the hypothesis that miRNAs-208a, -208b, and -499 can serve as noninvasive biomarkers for the extent of myocardial damage and the postoperative clinical course of pediatric patients with congenital heart defects (CHDs) at an early time point following surgery. Serum samples were obtained from 79 pediatric patients before and 6, 12, and 24 h after surgery. MiRNAs-208a, -208b, and -499 were quantified by RQ-PCR. Correlations between the patient's clinical variables and miRNA levels were tested. Our results show that the levels of the three miRNAs were elevated at 6 h after surgery, remained high at 12 h and declined at 24 h after the operation. The amount of all three miRNAs at 6 h after surgery correlated with surgical and laboratory parameters. Their amount at 12 h after surgery correlated with the length of stay at the hospital. Expression levels of miRNA-208a at 6 h were related to the appearance of cardiac complications, and could predict whether a patient will sustain complications or will be ventilated for more than 48 h after surgery. Circulating miRNA-208a is a predictor for the risk of developing cardiac complications during the postoperative course as early as 6 h after heart surgery for CHD in pediatric patients.

Effects of propofol and etomidate anesthesia on cardiovascular miRNA expression: the different profiles?

Background

The effects of the intravenous anesthetics propofol and etomidate on circulation are significantly different; however, their differing effects on miRNA expression in the cardiovascular system are not clearly understood. The purpose of this study is to investigate the effects of these two anesthetics on miRNA expression profiles in the heart and blood vessels.

Methods

Rats were randomly divided into a propofol group and an etomidate group. Spontaneous breathing was maintained throughout the anesthesia process and the rats’ oxygen supply was ensured. Heart and thoracic aorta tissue was harvested 3 h after induction. The expression profiles of cardiovascular miRNAs were detected by microarray 4.0 analysis. Twelve representative miRNAs were selected for qRT-PCR validation, and their target genes were predicted using bioinformatics methods.

Results

Microarray analysis showed 16 differentially expressed miRNAs in heart tissue from the propofol group compared with the etomidate group (10 up-regulated and 6 down-regulated), while in the blood vessels there were 25 altered miRNAs (10 up-regulated, 15 down-regulated). After verifying 12 representative miRNAs via qRT-PCR, the results showed no significant difference in the expression of miRNAs in the heart tissue, but a significant difference in the expression of 5 miRNAs in vessel tissue between the two groups. Bioinformatics analysis predicts that the target genes of the 5 differentially expressed miRNAs are associated with chemical synapse signaling pathways.

Conclusions

Propofol and etomidate have different effects on the expression of cardiovascular miRNAs, and further research is needed to elucidate the functional consequences of these differentially expressed miRNAs.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0610-9) contains supplementary material, which is available to authorized users.

MicroRNA 199a Is Downregulated in Patients After Coronary Artery Bypass Graft Surgery and Is Associated with Increased Levels of Sirtuin 1 (SIRT 1) Protein and Major Adverse Cardiovascular Events at 3-Year Follow-Up

Background

The cardioprotective protein SIRT1 is elevated in patients with coronary artery disease (CAD) to compensate for the disease-related adverse effects, but less is known about the prognostic role of SIRT 1 regulating microRNAs in patients after coronary artery bypass graft (CABG) surgery.

Material/Methods

The expression of the SIRT 1-specific microRNAs miR-199a and miR-195 was analyzed using real-time PCR in 68 patients referred for CABG surgery and 34 control patients undergoing heart valve surgery. In CABG patients, major adverse cardiac and cerebrovascular events (MACCEs), including all-cause death, myocardial infarction (MI), re-vascularization, heart failure symptoms ≥NYHA II, re-hospitalization for any cardiovascular reason, and stroke, were analyzed at a median follow-up (FU) of 3.2 years (range: 3.0–3.6).

Results

The level of miR-199a in patients with CAD was significantly reduced compared to the control group (relative expression: 0.89±0.49 vs. 1.90±0.90, p=0.001), while SIRT 1 protein was markedly enhanced (p<0.001). In patients undergoing CABG who had MACCEs, miR-199a was significantly lower compared to patients with an uneventful FU (0.71±0.25 vs. 0.98±0.53, p=0.007). Heart failure status, death, and total MACCEs rate were inversely correlated with the amount of miR-199a (p=0.039) at 3-year FU.

Conclusions

Altered expression of miR-199a in myocardial tissue was found to be associated with SIRT 1 upregulation in patients with CAD undergoing CABG and was associated with an increased MACCEs rate at mid-term follow-up.

Non-coding RNAs as biomarkers for acute myocardial infarction

Acute myocardial infarction (AMI) is a main threat to human lives worldwide. Early and accurate diagnoses warrant immediate medical care, which would reduce mortality and improve prognoses. Circulating non-coding RNAs have been demonstrated to serve as competent biomarkers for various diseases. Following the identification of cardiac-specific microRNA miR-208a in circulation, more non-coding RNAs (miR-1, miR-499 and miR-133) have been identified as biomarkers not only for the diagnosis of AMI but also for prognosis post infarction. Here, we summarized recent findings on non-coding RNAs as biomarkers for early diagnosis of ST-segment elevation myocardial infarction and for disease monitoring of myocardial infarction. In addition, the prognostic potential of non-coding RNAs in patients treated with percutaneous coronary intervention was also described. We also include studies based on biobanks, and build a miRNA release spectrum after AMI, which provides quantitative and time-lapse monitoring of AMI progress. With this spectrum, we are able to customize personal medical care, which prevents further damage. By constructing a network of circulating non-coding RNAs with high specificity and sensitivity, detailed diagnostic information was provided for personalized medicine. Unveiling the roles and kinetics of circulating non-coding RNAs may lead to a revolution in clinical diagnosis.

miRNAS in cardiovascular diseases: potential biomarkers, therapeutic targets and challenges

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the world. Although considerable progress has been made in the diagnosis, treatment and prognosis of CVD, there is still a critical need for novel diagnostic biomarkers and new therapeutic interventions to decrease the incidence of this disease. Recently, there is increasing evidence that circulating miRNAs (miRNAs), i.e. endogenous, stable, single-stranded, short, non-coding RNAs, can be used as diagnostic biomarkers for CVD. Furthermore, miRNAs represent potential novel therapeutic targets for several cardiovascular disorders. In this review we provides an overview of the effects of several CVD; including heart failure, acute myocardial infarction, arrhythmias and pulmonary hypertension; on levels of circulating miRNAs. In addition, the use of miRNA as therapeutic targets is also discussed, as well as challenges and recommendations in their use in the diagnosis of CVD.

Association of MIR-499a expression and seed region variant (rs3746444) with cardiovascular disease in Egyptian patients

BACKGROUND

Circulating microRNAs could be powerful markers of acute myocardial infarction (MI) and its functional genetic variants could increase susceptibility to cardiovascular disease (CVD). The current study aimed to quantify the microRNA (miR)-499a levels in serum of MI patients compared to hypertensive and healthy subjects and to investigate the association of its A/G variant rs3746444 with CVD in a sample of an Egyptian population.

METHODS

Serum miR-499a relative expressions were measured in 110 acute MI patients, 76 hypertensive patients, and 121 healthy controls by Real-time quantitative polymerase chain reaction. MIR-499a genotyping was performed for an additional 107 coronary artery disease patients by Real-time allele discrimination assay.

RESULTS

Acute MI patients showed high relative expression of miR-499a (> 105-fold, p < .001), and it was nearly undetectable in healthy controls and hypertensive patients. It showed an area under the curve of 0.953, with a sensitivity of 97.2% and a specificity of 75.0%. ST-elevation MI (STEMI) patients had higher miR-499a serum levels than patients with Non-STEMI. There was a significant association of MIR-499a variant with acute MI but not with hypertension under all genetic models tested. As a new finding, in overall and stratified analysis, the miR-499a variant was not correlated with its expression profile.

CONCLUSIONS

Circulating miR-499a levels could be a useful biomarker, discriminating acute MI within 12 hours from healthy subjects. Its variant rs3746444 A/G is associated with increased susceptibility to acute MI and CAD in Egyptian population.

Establishment of an easy and straight forward heparinase protocol to analyse circulating and myocardial tissue micro-RNA during coronary artery-bypass-graft surgery

Coronary artery-bypass-graft (CABG) surgery is associated with myocardial damage and increased blood concentrations of circulating microRNAs (miRNA). However, whether and to what extent these miRNAs relate to cardiac tissue miRNA expression have not yet been explored. Since plasma miRNA quantification in samples from cardiopulmonary bypass (CPB) patients is severely hampered by heparin, we established and validated successfully a protocol to reliably measure miRNA in 49 heparinized patients undergoing CABG so as to investigate the relationship between circulating and right atrial miRNAs. Plasma and right atrial expression of miR-1, miR-133a, miR-423-5p, and miR-499 were measured before and after CPB, as well as miRNAs in plasma 24 h thereafter. All plasma miRNAs increased significantly with surgery while cardiac tissue expression of only miR-133a (1.4-fold; p = 0.003) and miR-423-5p (1.3 fold; p = 0.025) increased as well. Right atrial and plasma miR-133a expression correlated positively before CPB (r = 0.288, p = 0.045) but miR-499 expression inversely (r = −0.484, p = 0.0004). There was a strong association between plasma miR-133a and miR-499 concentrations and postoperative troponin I concentrations, the marker for myocardial damage. Increased myocardial miR-133a and miR-423-5p expression together with unchanged miR-1 and miR-499 expression might suggest active release of these miRNAs rather than their origin from damaged cells.

MiRroring the Multiple Potentials of MicroRNAs in Acute Myocardial Infarction

At present, cardiovascular diseases are depicted to be the leading cause of death worldwide according to the World Health Organization. In the future, projections predict that ischemic heart disease will persist in the top main causes of illness. Within this alarming context, some tiny master regulators of gene expression programs, namely, microRNAs (miRNAs) carry three promising potentials. In fact, miRNAs can prove to be useful not only in terms of biomarkers allowing heart injury detection but also in terms of therapeutics to overcome limitations of past strategies and treat the lesions. In a more creative approach, they can even be used in the area of human engineered cardiac tissues as maturation tools for cardiomyocytes (CMs) derived from pluripotent stem cell. Very promising not only for patient-specific cell-based therapies but also to develop biomimetic microsystems for disease modeling and drug screening, these cells greatly contribute to personalized medicine. To get into the heart of the matter, the focus of this review lies primarily on miRNAs as acute myocardial infarction (AMI) biomarkers. Only large cohort studies comprising over 100 individuals to reach a potent statistical value were considered. Certain miRNAs appeared to possibly complement protein-based biomarkers and classical risk factors. Some were even described to bear potential in the discrimination of similar symptomatic pathologies. However, differences between pre-analytical and analytical approaches substantially influenced miRNA data. Further supported by meta-analysis studies, this problem had to be addressed. A detailed critical analysis of each step to define miRNAs biomarker potential is provided to inspire a future improved universal strategy. Interestingly, a recurrent set of cardiomyocyte-enriched miRNAs was found, namely, miR-1; miR-133; miR-208a/b; and miR-499a. Each member of this myomiRs group displayed promising roles either individually or in combination as AMI diagnostic or prognostic biomarkers. Furthermore, a precise combo was shown to be powerful enough to transdifferentiate human fibroblasts into CMs opening doors in the therapeutics. Following these discoveries, they also emerged as optional tools to transfect in order to mature CMs derived from pluripotent stem cells. Ultimately, the multiple potentials carried by the myomiRs miR-1; miR-133; miR-208a/b; and miR-499a still remain to be fully unveiled.

Modified high-throughput quantification of plasma microRNAs in heparinized patients with coronary artery disease using heparinase

Heparin, a widely used anticoagulant in cardiovascular diseases, is notorious for its inhibitory effect on qRT-PCR-based detection. Heparinase I could degrade heparin in RNA. qRT-PCR-based TaqMan Low Density Array (TLDA) technology is commonly used for circulating microRNAs (miRNAs) profiling analysis. However, the effect of heparin contamination on inhibition of miRNAs TLDA amplification, as well as the method for removing heparin during this process, are not yet well investigated. We obtained the plasma RNA samples from patients undergoing percutaneous coronary intervention (PCI) before and after heparinization (n = 26). We found that heparin suppressed the miRNAs amplification by ∼8 cycles in the TLDA assay, which was absolutely reversed after treating the RNA samples with heparinase I using the components from TLDA reverse transcription system. We further observed that heparin inhibited the miRNAs amplification by ∼4 cycles in the qRT-PCR assay, which was also reversed by heparinase I using the similar method. Furthermore, we demonstrated that plasma miR-92a and miR-155 were differentially expressed in the patients undergoing PCI tested by TLDA assay, which was validated by qRT-PCR. In conclusion, we present a simple method for the removal of heparin with heparinase I, and for the subsequent successful miRNAs TLDA or RT-qPCR amplification.

miRNAs as potential therapeutic targets and diagnostic biomarkers for cardiovascular disease with a particular focus on WO2010091204

INTRODUCTION

A number of miRNAs have been reported to be critically involved in the regulation of cardiovascular disease (CVDs). Therefore, the development of potent analogues/inhibitors for miRNAs have thus become a key focus in the present drug discovery. In this review, we discuss the basic research and clinical use of miRNAs as the early diagnosis and therapeutic targets for CVD. We have also focused on the efficiency of therapeutically targeting miR-499, which is considered as one of the most promising molecules for treating CVDs. Areas covered: In this review, we have discussed the patents and patent applications related to miRNAs detected in CVD patients published in recent years. This review also covers the expression pattern of miR-499, as well as it highlights functions of its inhibitors in CVD. We used Google and Pubmed search engines to find relevant patents. Expert opinion: Although a massive number of miRNAs are patented as CVD biomarkers, further work is absolutely required to evaluate the reliable diagnostic values and therapeutic potential of these candidates. Overall, targeting miRNAs is definitely a promising strategy to be investigated for diagnosis and treatment of CVDs in future, however, the delivery system and off-targets effects are still a difficult challenge need to be elucidated.

Circulating Noncoding RNAs as Biomarkers of Cardiovascular Disease and Injury

The discovery of thousands of noncoding RNAs (ncRNAs) has expanded our view on mammalian genomes and transcriptomes, as well as their organization and regulation. Accumulating evidence on aberrantly regulated ncRNAs, including short microRNAs, long ncRNAs and circular RNAs, across various heart diseases indicates that ncRNAs are critical contributors to cardiovascular pathophysiology. In addition, ncRNAs are released into the circulation where they are present in concentration levels that differ between healthy subjects and diseased patients. Although little is known about the origin and function of such circulating ncRNAs, these molecules are increasingly recognized as noninvasive and readily accessible biomarker for risk stratification, diagnosis and prognosis of cardiac injury, and multiple forms of cardiovascular disease. In this review, we summarize recent findings on biological characteristics of circulating ncRNAs and highlight their value as potential biomarker in selected pathologies of cardiovascular disease.

Assessment of the Procoagulant Activity of Microparticles and the Protein Z System in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery

To understand the coagulation changes after off-pump coronary artery bypass (OPCAB) surgery, we evaluated the procoagulant activity of microparticles (MPs) and microparticles exposing tissue factor (MPs-TF), together with the levels of total tissue factor (TF), protein Z (PZ), protein Z-dependent protease inhibitor (ZPI), and factor X (FX) before (first day) and 1 week after surgery (seventh day) in plasma samples from 30 patients. Twenty healthy controls were also included. Compared to the controls, patients scheduled for surgery had significantly higher MPs-TF procoagulant activity and lower TF levels ( P = .0006, P = .02, respectively). In the whole cohort, median procoagulant activity of MPs-TF and median levels of TF and ZPI were significantly lower ( P = .02, P = .0003, and P = .004, respectively), while median levels of PZ and FX were significantly higher ( P = .02 and P = .002, respectively) on the seventh day compared to the first day. Our results suggest that OPCAB surgery has a significant effect on the procoagulant activity of MPs-TF and the PZ system.

Circular RNAs in Cardiovascular Disease: An Overview

Circular RNA (circRNA), a novel type of endogenous noncoding RNA (ncRNA), has become a research hotspot in recent years. CircRNAs are abundant and stably exist in creatures, and they are found with covalently closed loop structures in which they are quite different from linear RNAs. Nowadays, an increasing number of scientists have demonstrated that circRNAs may have played an essential role in the regulation of gene expression, especially acting as miRNA sponges, and have described the potential mechanisms of several circRNAs in diseases, hinting at their clinical therapeutic values. In this review, the authors summarized the current understandings of the biogenesis and properties of circRNAs and their functions and role as biomarkers in cardiovascular diseases.

Modulating microRNAs in cardiac surgery patients: Novel therapeutic opportunities?

This review focuses on microRNAs (miRs) in cardiac surgery, where they are emerging as potential targets for therapeutic intervention as well as novel clinical biomarkers. Identification of the up/down-regulation of specific miRs in defined groups of cardiac surgery patients can lead to the development of novel strategies for targeted treatment in order to maximise therapeutic results and minimise acute, delayed or chronic complications. MiRs could also be involved in determining the outcome independently of complications, for example in relation to myocardial perfusion and fibrosis. Because of their relevance in disease, their known sequence and pharmacological properties, miRs are attractive candidates for therapeutic manipulation. Pharmacological inhibition of individual miRs can be achieved by modified antisense oligonucleotides, referred to as antimiRs, while miR replacement can be achieved by miR mimics to increase the level of a specific miR. MiR mimics can restore the function of a lost or down-regulated miR, while antimiRs can inhibit the levels of disease-driving or aberrantly expressed miRs, thus de-repressing the expression of mRNAs targeted by the miR. The main delivery methods for miR therapeutics involve lipid-based vehicles, viral systems, cationic polymers, and intravenous or local injection of an antagomiR. Local delivery is particularly desirable for miR therapeutics and options include the development of devices specific for local delivery, light-induced antimiR, and vesicle-encapsulated miRs serving as therapeutic delivery agents able to improve intracellular uptake. Here, we discuss the potential therapeutic use of miRNAs in the context of cardiac surgery.

Comparison of miRNA signature versus conventional biomarkers before and after off-pump coronary artery bypass graft

Circulating levels of microRNAs (miRNAs) and their expression patterns are supposed to serve as signatures for diagnosis or prognosis of cardiovascular events. The present study aimed at determining if there is any correlation between the release pattern of 2 miRNAs and the plasma levels of conventional biomarkers cardiac troponin I (cTnI), creatine kinase (CK) and uric acid (UA) in patients undergoing their first off-pump coronary artery bypass graft (OCABG). Seventy OCABG patients (69% men, aged 59.2±8.2years) were enrolled. Emergencies, re-operations, abnormal preoperative serum cTnI and combined procedures were excluded from this study. Pre-operative mean ejection fraction was 45.8±8.6%, the average number of grafts was 3±0.87/patient, and the internal mammary artery was used for all. Beside conventional clinical assays, we performed real-time quantitative PCR to analyze the circulating levels of miR-155, miR-126 and miR-499 at 1day before surgery as well as 4days after surgery. Importantly, there was no report of myocardial infarction in our patients, pre- or post-operatively. In contrast to conventional biomarkers cTnI and CK, circulating levels of miRNAs decreased significantly (P<0.01) after revascularization surgery. A significant positive correlation was seen between the cTnI and miR-499 (r∼0.53, P<0.01) and between miR-126 and UA (r∼0.5, P<0.01). Time course study of circulating miR-499, miR-126 and miR-155 in cardiac surgery clarified their advantage and correlations to the traditional biomarkers cTnI, total CK, CK-MB and UA. Our results suggest that this signature is a novel, early biomarker which indicates myocardial ischemia in cardiac surgery. It could be postulated that the application of these miRNAs may be considered for monitoring of response to pharmacological interventions aimed at reducing cardiac ischemia, especially in OCABG candidates.

Prospective and therapeutic screening value of non-coding RNA as biomarkers in cardiovascular disease

Non-coding RNA (ncRNA) is a class of genetic, epigenetic and translational regulators, containing short and long transcripts with intriguing abilities for use as biomarkers due to their superordinate role in disease development. In the past five years many of these have been investigated in cardiovascular diseases (CVD), mainly myocardial infarction (MI) and heart failure. To extend this view, we summarize the existing data about ncRNA as biomarker in the whole entity of CVDs by literature-based review and comparison of the identified candidates. The myomirs miRNA-1, -133a/b, -208a, -499 with well-defined cellular functions have proven equal to classic protein biomarkers for disease detection in MI. Other microRNAs (miRNAs) were reproducibly found to correlate with disease, disease severity and outcome in heart failure, stroke, coronary artery disease (CAD) and aortic aneurysm. An additional utilization has been discovered for therapeutic monitoring. The function of long non-coding transcripts is only about to be unraveled, yet shows great potential for outcome prediction. ncRNA biomarkers have a distinct role if no alternative test is available or has is performing poorly. With increasing mechanistic understanding, circulating miRNA and long non-coding transcripts will provide useful disease information with high predictive power.

Circulating miR-499 as a potential biomarker for acute myocardial infarction

Acute myocardial infarction (AMI), a common heart disease that may lead to chronic heart failure, is the leading cause of morbidity and mortality worldwide. MicroRNAs (miRNAs) are small non-coding RNAs that mediate the expression of target genes. Recently, a number of miRNAs are emerging as potential biomarkers of AMI. MiRNA-499 is a newly discovered member of miRNAs, and is mainly expressed in myocardium, the circulating levels of miRNA-499 was increased in AMI patients. This review summarizes the latest advances in the miRNA-499 study and discusses the potential of miRNA-499 to be a biomarker of AMI.

Circulating miR-126 and miR-499 reflect progression of cardiovascular disease; correlations with uric acid and ejection fraction

BACKGROUND

The aim of this study was to assess plasma levels of endothelium- and heart-associated microRNAs (miRNAs) miR-126 and miR-499, respectively, using quantitative reverse transcriptase polymerase chain reaction.

METHODS

A two-step analysis was conducted on 75 patients undergoing off-pomp coronary artery bypass graft (CABG) surgery. Five biomarkers of inflammation and cardiac injury were assessed in addition to the above-mentioned miRNAs.

RESULTS

Plasma concentrations of miRNAs were found to be significantly correlated with plasma levels of cardiac troponin I (cTnI) (miR-499, r 0.49, p~0.002; miR-126, r = 0.30, p~0.001), indicating cardiac damage. Data analysis revealed that miR-499 had higher sensitivity and specificity for cardiac injury than miR-126, which reflects more endothelial activation. Interestingly, a strong correlation was observed between both miRNAs and uric acid (UA) levels with ventricular contractility measured as ejection fraction (EF) (miR-499/EF%, r = 0.58, p~0.004; UA/EF%, r = -0.6, p~0.006; UA/miR-499, r = -0.34; UA/miR-126, r = 0.5, p~0.01).

CONCLUSIONS

In patients undergoing CABG, circulating miR-126/499 is associated with presentation of traditional risk factors and reflects post-operative response to injury. Plasma pool of miRNAs likely reflects extracellular miRNAs which are proportional to intracellular miRNA levels. Therefore, circulating levels of these miRNAs have prognostic implications in detection of higher risk of future cardiovascular events.

Heparinase treatment of heparin-contaminated plasma from coronary artery bypass grafting patients enables reliable quantification of microRNAs

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Plasma collected before cardiac surgery also contain variable amounts of heparin.

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Evaluation of RT-qPCR inhibition is recommended for all types of clinical samples.

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Heparinase treatment completely eliminated widely different levels of inhibition.

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Heparinase treatment causes different (1.5- to 6.5-fold) decrease in the amount of detected RNA for different targets.

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Heparinase treatment did not influence the technical variability RNA quantification, neither at high nor at low concentration of targets.

Background

microRNAs have recently been identified as powerful biomarkers of human disease. Reliable polymerase chain reaction (PCR)-based quantification of nucleic acids in clinical samples contaminated with polymerase inhibitor heparin requires deheparinization. However, the effects of deheparinization procedure on quantification of nucleic acids remain largely unknown. The aim of this study was to determine whether the deheparinization procedure completely eliminates the inhibition of amplification, while maintaining RNA integrity and technical variability of the measured microRNA levels.

Methods

Heparinized plasma from 9 patients undergoing coronary artery bypass grafting (CABG) and the heparin-free plasma from 58 rats were spiked with a synthetic RNA oligonucleotide and total RNA was extracted. The RNA solutions were then treated with heparinase I to remove contaminating heparin prior to reverse transcription. Levels of synthetic spike-in RNA oligonucleotide, as well as endogenous hsa-miR-1-3p and hsa-miR-208a-3p, were measured using quantitative reverse transcription PCR (RT-qPCR). The amplification efficiency and presence of inhibitors in individual samples were directly determined using calibration curves.

Results

In contrast to RNA samples from rat plasma, RNA samples derived from the CABG patient plasma contained inhibitors, which were completely eliminated by treatment with heparinase. The procedure caused a decrease in the amount of detected RNA; however, the technical variability of the measured targets did not change, allowing for the quantification of circulating endogenous hsa-miR-1-3p and hsa-miR-208a-3p in the plasma of CABG patients.

Conclusions

The heparinase treatment procedure enables utilization of RT-qPCR for reliable microRNA quantification in heparinized plasma.

Micro-RNA-208a, -208b, and -499 as Biomarkers for Myocardial Damage After Cardiac Surgery in Children

OBJECTIVES

To test the hypothesis that cardiac-enriched micro-RNAs can serve as accurate biomarkers that reflect myocardial injury and to predict the postoperative course following pediatric cardiac surgery. Micro-RNAs have emerged as plasma biomarkers for many pathologic states. We aimed to quantify preoperative and postoperative plasma levels of cardiac-enriched micro-RNA-208a, -208b, and -499 in children undergoing cardiac surgery and to evaluate correlations between their levels, the extent of myocardial damage, and the postoperative clinical course.

DESIGN

PICU.

PATIENTS

Thirty pediatric patients that underwent open heart surgery for the correction of congenital heart defects between January 2012 to July 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At 12 hours post surgery, the plasma levels of the micro-RNAs increased by 300- to 4,000-fold. At 24 hours, their levels decreased but remained significantly higher than before surgery. Micro-RNA levels were associated with troponin levels, longer cardiopulmonary bypass and aortic crossclamp times, maximal postoperative aspartate aminotransferase levels, and delayed hospital discharge.

CONCLUSIONS

Circulating micro-RNA-208a, -208b, and -499 are detectable in the plasma of children undergoing cardiac surgery and may serve as novel biomarkers for monitoring and forecasting postoperative myocardial injury and recovery.

Long Noncoding RNA MHRT Protects Cardiomyocytes against H2O2-Induced Apoptosis

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. The exploration of new biomarkers with high sensitivity and specificity for early diagnosis of AMI therefore becomes one of the primary task. In the current study, we aim to detect whether there is any heart specific long noncoding RNA (lncRNA) releasing into the circulation during AMI, and explore its function in the neonatal rat cardiac myocytes injury induced by H2O2. Our results revealed that the cardiac-specific lncRNA MHRT (Myosin Heavy Chain Associated RNA Transcripts) was significantly elevated in the blood from AMI patients compared with the healthy control ((*) p<0.05). Using an in vitro neonatal rat cardiac myocytes injury model, we demonstrated that lncRNA MHRT was upregulated in the cardiac myocytes after treatment with hydrogen peroxide (H2O2) via real-time RT-PCR (qRT-PCR). Furthermore, we knockdowned the MHRT gene by siRNA to confirm its roles in the H2O2-induced cardiac cell apoptosis, and found that knockdown of MHRT led to significant more apoptotic cells than the non-target control ((**) p<0.01), indicating that the lncRNA MHRT is a protective factor for cardiomyocyte and the plasma concentration of MHRT may serve as a biomarker for myocardial infarction diagnosis in humans AMI.

Interaction between microRNA expression and classical risk factors in the risk of coronary heart disease

The aim of this study was to identify the synergistic effect of microRNA expression with classical risk factors of coronary heart disease (CHD) and to explore their diagnostic value for coronary stenotic lesions in subjects with CHD. Plasma samples were obtained from 66 subjects with CHD and from 58 control individuals. A quantitative reverse-transcription PCR (RT-qPCR) assay was conducted to confirm the relative expressions of the known CHD-related miRNAs. The severity of coronary atherosclerosis was based on the Gensini scoring system. The expression of miR-125b in plasma of the CHD group was lower than that of the non-CHD group (0.14 ± 0.09 vs. 0.18 ± 0.10, p = 0.055), and the miR-125b levels significantly decreased following an increasing Gensini score (P = 0.037). Spearman correlation analyses indicated the Gensini score was negatively associated with miR-125b (r = −0.215, p = 0.017). Of all the miRNAs, miR-125b showed the lowest AUC (0.405; 95% CI: 0.305 ~ 0.506, p = 0.070). We found several synergistic effects between miR-125b and classical risk factors, such as age, sex, CR, FBG and HDL-C; the proportion of CHD attributable to the interaction of miR-125b and age was as high as 80%. Therefore, miR-125b was shown to play an important role in individual’s susceptibility to developing CHD.

Beyond the Limits: Clinical Utility of Novel Cardiac Biomarkers

Preoperative assessment of cardiovascular risk is essential when it comes to extensive noncardiac surgery procedures. Therefore, accurate and timely diagnosis of myocyte damage is vital. In modern medical practice it is believed that the so-called "multimarker" approach is the most appropriate and most accurate, but new research points out that there are novel biomarkers which could be used independently. Studies that evaluate miRNA, H-FABP, and MR-PAMP give encouraging results. When it comes to miRNA clinical studies show high statistical significance, especially in the case of acute myocardial infarction (P = 0.001). Statistical significance of P = 0.007 was found in acute coronary syndrome, when H-FABP was measured. Biochemical marker MR-PAMP showed statistical significance of P < 0.0001 in most clinical studies.

Epitranscriptional regulation of cardiovascular development and disease

Development, homeostasis and responses to stress in the heart all depend on appropriate control of mRNA expression programmes, which may be enacted at the level of DNA sequence, DNA accessibility and RNA-mediated control of mRNA output. Diverse mechanisms underlie promoter-driven transcription of coding mRNAs and their translation into protein, and the ways in which sequence alteration of DNA can make an impact on these processes have been studied for some time. The field of epigenetics explores changes in DNA structure that influence its accessibility by transcriptional machinery, and we are continuing to develop our understanding of how these processes modify cardiac RNA production. In this topical review, we do not focus on how DNA sequence and methylation, and histone interactions, may alter its accessibility, but rather on newly described mechanisms by which some transcribed RNAs may alter initial transcription or downstream processing of other RNAs, involving both short non-coding RNAs (microRNAs) and long non-coding RNAs (lncRNAs). Here we present examples of how these two classes of non-coding RNAs mediate widespread effects on cardiac transcription and protein output in processes for which we use the broad term 'epitranscriptional regulation' and that are complementary to the DNA methylation and histone modification events studied by classical epigenetics.