Circulating microRNA Profiling Needs Further Refinement Before Clinical Use in Patients With Aortic Stenosis

Qiliqiangxin capsule alleviates cardiac hypertrophy and cardiac dysfunction by regulating miR-382-5p/ATF3 axis

OBJECTIVE

Qiliqiangxin Capsule (QL) was investigated for its possible role in cardiac hypertrophy in this study.

METHODS

QL (0.5 mg/mL) was pre-treated in Neonatal Mouse Ventricular Cardiomyocytes (NMVCs) before induction of cardiomyocyte hypertrophy by Angiotensin II (Ang-II). Immunofluorescence staining for α-actinin was conducted to determine cell surface area. Atrial Natriuretic Peptide (ANP) and Brain Natriuretic Peptide (BNP) of hypertrophy markers were examined. Ang-II infusion was given to stimulate cardiac hypertrophy in mice. The cardiac function of mice was detected by echocardiography, and the pathological status of myocardial tissue was observed.

RESULTS

The surface of cardiomyocytes was enlarged by Ang-II, and ANP and BNP levels were increased. QL processing could save these changes. miR-382-5p was upregulated in Ang-II-treated NMVCs, and reducing miR-382-5p could further enhance the therapeutic effect of QL while elevating miR-382-5p weakened the protective effect of QL. QL could inhibit miR-382-5p expression to negatively regulate Activated Transcription Factor 3 (ATF3) expression. Enhancing ATF3 expression rescued miR-382-5p upregulation-mediated role in NMVCs. In addition, QL alleviated Ang-II-stimulated cardiac hypertrophy and cardiac dysfunction in mice.

CONCLUSION

QL may alleviate cardiac hypertrophy and cardiac dysfunction via the miR-382-5p/ATF3 axis.

Biomarkers as Prognostic Markers for Aortic Stenosis: A Review

Aortic stenosis (AS) is the most frequent valvular heart disease among the older individuals. Current guidelines indicate intervention for patients with symptomatic or fast progressive severe AS and asymptomatic patients with a reduced left ventricular (LV) ejection fraction by 50%. Interestingly, myocardial damage may have already happened by the time symptoms appear or LV function deteriorates. Serum biomarkers can be an early indicator to show LV function decline and AS progression even before clinical symptom onset. Studies have shown that cardiac biomarkers have prognostic value in patients with AS. Hence, cardiac biomarkers can be helpful in determining the optimum time to intervene. Transcatheter aortic valve replacement is a less invasive alternative to conventional surgical aortic valve replacement. The elevation of cardiac biomarkers at discharge has been associated with 2-year mortality after transcatheter aortic valve replacement. The correlation between biomarkers and AS-associated morbidity and mortality is an area to explore further. The authors of this review article have discussed the role of cardiac biomarkers in patients with AS for better risk stratification and identification of patients who would benefit from early intervention.

The Role of MicroRNAs in Aortic Stenosis-Lessons from Recent Clinical Research Studies

Aortic stenosis (AS) is the most prevalent primary valve lesion demanding intervention. Two main treatment options are surgical aortic valve replacement or transcatheter aortic valve implantation. There is an unmet need for biomarkers that could predict treatment outcomes and become a helpful tool in guiding Heart Team in the decision-making process. Micro-ribonucleic acids (microRNAs/miRs) have emerged as potential biomarkers thoroughly studied in recent years. In this review, we aimed to summarize the current knowledge about the role of miRNAs in AS based on human subject research. Much research investigating miRNAs' role in AS has been conducted so far. We included 32 original human subject research relevant to the discussed field. Most of the presented miRNAs were studied only by a single research group. Nevertheless, several miRNAs appeared more than once, sometimes with high consistency between different studies but sometimes with apparent discrepancies. The molecular aspects of diseases are doubtlessly exciting and provide invaluable insights into the pathophysiology. Nevertheless, translating these findings, regarding biomarkers such as miRNAs, into clinical practice requires much effort, time, and further research with a focus on validating existing evidence.

Peripheral blood RNA biomarkers for cardiovascular disease from bench to bedside: a position paper from the EU-CardioRNA COST action CA17129

Despite significant advances in the diagnosis and treatment of cardiovascular diseases, recent calls have emphasized the unmet need to improve precision-based approaches in cardiovascular disease. Although some studies provide preliminary evidence of the diagnostic and prognostic potential of circulating coding and non-coding RNAs, the complex RNA biology and lack of standardization have hampered the translation of these markers into clinical practice. In this position paper of the CardioRNA COST action CA17129, we provide recommendations to standardize the RNA development process in order to catalyse efforts to investigate novel RNAs for clinical use. We list the unmet clinical needs in cardiovascular disease, such as the identification of high-risk patients with ischaemic heart disease or heart failure who require more intensive therapies. The advantages and pitfalls of the different sample types, including RNAs from plasma, extracellular vesicles, and whole blood, are discussed in the sample matrix, together with their respective analytical methods. The effect of patient demographics and highly prevalent comorbidities, such as metabolic disorders, on the expression of the candidate RNA is presented and should be reported in biomarker studies. We discuss the statistical and regulatory aspects to translate a candidate RNA from a research use only assay to an in-vitro diagnostic test for clinical use. Optimal planning of this development track is required, with input from the researcher, statistician, industry, and regulatory partners.

miR-22-3p as a potential biomarker for coronary artery disease based on integrated bioinformatics analysis

Background: Coronary artery disease (CAD) is a common cardiovascular disease that has attracted attention worldwide due to its high morbidity and mortality. Recent studies have shown that abnormal microRNA (miRNA) expression is effective in CAD diagnoses and processes. However, the potential relationship between miRNAs and CAD remains unclear.

Methods: Microarray datasets GSE105449 and GSE28858 were downloaded directly from the Gene Expression Omnibus (GEO) to identify miRNAs involved in CAD. Target gene prediction and enrichment analyses were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).

Results: There were nine differentially expressed miRNAs in CAD patients compared to the controls. A total of 352 genes were predicted and subjected to GO analysis, which showed that differentially expressed genes (DEGs) were mainly associated with axon guidance, neuron projection guidance, neuron-to-neuron synapses, and postsynaptic density. According to the KEGG pathway analysis, the most enriched pathways were those involved in transcriptional misregulation in cancer, growth hormone synthesis, secretion and action, endocrine resistance, axon guidance, and Cushing syndrome. Pathway analysis was mainly involved in the HIPPO and prion disease signaling pathways. Furthermore, a competing endogenous RNA (ceRNA) interaction network centered on miR-22-3p revealed eight related transcription factors in the cardiovascular system. The receiver operating characteristic (ROC) curve analysis suggested that miR-22-3p may be a better CAD predictor.

Conclusion: The results indicate that miR-22-3p may function in pathophysiological CAD processes. Our study potentiates miR-22-3p as a specific biomarker for diagnosing CAD.

A systematic review of micro-RNAs in aortic stenosis and cardiac fibrosis

Aortic stenosis (AS) is the commonest valve lesion requiring surgery in the Western world. The presence of myocardial fibrosis is associated with mortality even after valve replacement. MicroRNAs could serve as biomarkers of fibrosis and risk stratify patients for earlier intervention. This study aimed to systematically review reports of micro-RNA (miR) associated with fibrosis in AS and identify potential biomarkers. We searched EMBASE, Medline, and Web of Science up to May 2020. Studies that reported on the role of miRs in AS and cardiac fibrosis were included. Study quality was assessed using the Newcastle-Ottawa scale. Of 4230 reports screened, 25 were included. All studies were of low to moderate quality. MiRs were analyzed in myocardial tissue (n = 10), aortic valve tissue (n = 5), plasma (n = 5), and serum (n = 5). A total of 365 miRs were reported, of which only a few were reported in more than one paper (3 in the myocardium, 5 in the aortic valve, and 1 in plasma). miR-21 was upregulated in plasma and myocardial tissue. MiR-19b was downregulated in the myocardium. Papers reporting myocardial miR-1 contradicted each other, and miR-133a was associated with increased left ventricular mass regression post-surgery. In the aortic valve, miRs-665, 602 and 939 were downregulated, and miRs-193b and 214 were upregulated. The data on miR in fibrosis in AS is scarce and of low to moderate quality. Further studies are needed to identify novel miRs as biomarkers, especially at an earlier asymptomatic phase of the disease.

MicroRNA sequencing in patients with coronary artery disease – considerations for use as biomarker for thrombotic risk

MicroRNAs (miRNAs) are small RNAs integral in the regulation of gene expression. Analysis of circulating miRNA levels may identify patients with coronary artery disease (CAD) at risk for recurrent myocardial infarction (MI) after percutaneous coronary interventions (PCIs). Subjects with CAD were selected from the GENCATH cardiac catheterization biobank. Subjects with recurrent MI after PCI were compared with those without recurrent MI during follow‐up in the initial (n = 48) and replication cohort (n = 67). Next generation MiRNA sequencing was performed on plasma samples and whole blood samples fixed with PAXGENE tubes upon collection. Overall, 164 miRNAs derived from whole blood were differentially expressed in the replication cohort between subjects with and without recurrent MI events (p < 0.05), with 69 remaining significant after false‐discovery rate (FDR) correction. None of the miRNAs in plasma was significantly different by FDR among subjects with and without MI. Overall, correlation between direction of effects between plasma and whole blood assays was variable, and only two miRNAs were concordant and significant in both. Associations of miRNA with vascular disease, MI, and thrombosis were further explored. MiRNA profiling has potential as the future biomarker for disease prognosis and treatment response marker in secondary treatment of patients with CAD after PCI. Whole blood may be the preferred sample source as compared to plasma.

miR-21 and miR-146a: The microRNAs of inflammaging and age-related diseases

The first paper on "inflammaging" published in 2001 paved the way for a unifying theory on how and why aging turns out to be the main risk factor for the development of the most common age-related diseases (ARDs). The most exciting challenge on this topic was explaining how systemic inflammation steeps up with age and why it shows different rates among individuals of the same chronological age. The "epigenetic revolution" in the past twenty years conveyed that the assessment of the individual genetic make-up is not enough to depict the trajectories of age-related inflammation. Accordingly, others and we have been focusing on the role of non-coding RNA, i.e. microRNAs (miRNAs), in inflammaging. The results obtained in the latest 10 years underpinned the key role of a miRNA subset that we have called inflammamiRs, owing to their ability to master (NF-κB)-driven inflammatory pathways. In this review, we will focus on two inflammamiRs, i.e. miR-21-5p and miR-146a-5p, which target a variety of molecules belonging to the NF-κB/NLRP3 pathways. The interplay between miR-146a-5p and IL-6 in the context of aging and ARDs will also be highlighted. We will also provide the most relevant evidence suggesting that circulating inflammamiRs, along with IL-6, can measure the degree of inflammaging.

Modulation of miR-382-5p reduces apoptosis of myocardial cells after acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is a severe cardiovascular condition. Blocking the apoptosis of myocardial cells may mitigate AMI. Excessive expression of Stanniocalcin-1 (STC1) plays a protective role in the heart by inhibiting myocardial cell apoptosis. Here, we looked at the mechanism by which miR-382-5p regulates STC1 and affects myocardial cell apoptosis after AMI.

METHODS

An AMI mouse model with a descending anterior ligament coronary artery and an HL-1 cell model with reproducible hypoxia/reoxygenation (H/R) were established. For pathological changes in myocardial tissues, terminal deoxynucleotidyl transferase dUTP nick end labelling staining and haematoxylin and eosin staining were performed. STC1 mRNA and miR-382-5p levels were measured using quantitative real-time PCR. Protein levels of STC1 and apoptosis-related proteins were measured by western blotting. The 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide assay was used to detect cell viability, and a dual-luciferase reporter assay was carried out to verify potential targets of miR-382-5p.

RESULTS

The level of miR-382-5p was raised in myocardial tissues of AMI mice and H/R-induced HL-1 cells. Compared with the control group, the myocardial tissue cells in the AMI group were disordered, with evident necrosis of myocardial cells, apoptosis and inflammatory infiltration. Interference with miR-382-5p inhibited myocardial cell apoptosis after H/R, as well as inferior lactate dehydrogenase. Also, miR-382-5p adversely regulated STC1 and the expression of STC1 was increased after transfection with miR-382-5p antagomir. Furthermore, interference with miR-382-5p reduced myocardial cell apoptosis after H/R by increasing the expression level of STC1.

CONCLUSION

To summarise, our study showed an increase in miR-382-5p in myocardial tissues in the AMI mouse model. Interference with miR-382-5p reduced apoptosis of myocardial cells after AMI and the effect was achieved by increasing STC1 expression.

Diagnostic utility of circulating plasma microRNA-101a in severity of coronary heart disease

BACKGROUND

For evaluating the severity of coronary heart disease (CHD), coronary arteriography may not be available everywhere due to technical limitations. MicroRNA-101a (miR-101a) associated with inflammation and cholesterol homeostasis. However, whether it related to presence and stratification of CHD is still unknown.

AIM

We aim to evaluate the value of miR-101a in stratifying CHD patients.

METHODS

We enrolled 200 CHD patients and 100 controls, and 200 CHD patients were divided into two groups of low and high SYNTAX score (SYNTAX score ≤ 22 versus SYNTAX score ≥ 33). Intergroup comparisons of miR-101a level were compared among the controls and two groups of low and high SYNTAX score. Correlation between miR-101a and blood lipid profiles was analyzed. The logistic regression analysis were conducted to evaluate the risk factors of CHD.

RESULTS

Relative level of miR-101a in the controls, SYNTAX score ≤ 22 and SYNTAX score ≥ 33 group were 4.61 (1.24-8.91), 3.28 (0.58-6.75) and 2.29 (1.04-3.62), respectively (p < 0.001). All lipid profiles significantly associated with miR-101a expression (all p < 0.001). The odds ratio (OR) of miR-101a in univariate analysis was 0.41 (95% CI, 0.33-0.52). After adjusting for the traditional risk factors, such as blood profiles and history of smoking, the odds ratio of miR-101a was 0.63 (95% CI, 0.47-0.43), which closely associated with CHD (p = 0.002).

CONCLUSIONS

Circulating miR-101a may be considered as a novel biomarker for evaluating the presence and severity of CHD.

Integrative Multi-Omics Analysis in Calcific Aortic Valve Disease Reveals a Link to the Formation of Amyloid-Like Deposits

Calcific aortic valve disease (CAVD) is the most prevalent valvular heart disease in the developed world, yet no pharmacological therapy exists. Here, we hypothesize that the integration of multiple omic data represents an approach towards unveiling novel molecular networks in CAVD. Databases were searched for CAVD omic studies. Differentially expressed molecules from calcified and control samples were retrieved, identifying 32 micro RNAs (miRNA), 596 mRNAs and 80 proteins. Over-representation pathway analysis revealed platelet degranulation and complement/coagulation cascade as dysregulated pathways. Multi-omics integration of overlapping proteome/transcriptome molecules, with the miRNAs, identified a CAVD protein–protein interaction network containing seven seed genes (apolipoprotein A1 (APOA1), hemoglobin subunit β (HBB), transferrin (TF), α-2-macroglobulin (A2M), transforming growth factor β-induced protein (TGFBI), serpin family A member 1 (SERPINA1), lipopolysaccharide binding protein (LBP), inter-α-trypsin inhibitor heavy chain 3 (ITIH3) and immunoglobulin κ constant (IGKC)), four input miRNAs (miR-335-5p, miR-3663-3p, miR-21-5p, miR-93-5p) and two connector genes (amyloid beta precursor protein (APP) and transthyretin (TTR)). In a metabolite–gene–disease network, Alzheimer’s disease exhibited the highest degree of betweenness. To further strengthen the associations based on the multi-omics approach, we validated the presence of APP and TTR in calcified valves from CAVD patients by immunohistochemistry. Our study suggests a novel molecular CAVD network potentially linked to the formation of amyloid-like structures. Further investigations on the associated mechanisms and therapeutic potential of targeting amyloid-like deposits in CAVD may offer significant health benefits.

New potential modulators of CYP4F2 enzyme activity in angina pectoris: hsa-miR-24-3p and hsa-miR-34a-5p

Purpose: To find an association of relative expression of hsa-miR-24-3p and hsa-miR-34a-5p molecules and CYP4F2 enzyme activity in blood plasma of stable angina pectoris (AP) patients'.Materials and Methods: MiRNA gene expression analysis was performed on total RNA extracted from blood plasma, using quantitative real-time polymerase chain reaction. CYP4F2 enzyme levels were determined using commercial ELISA kit. In total, 32 AP and 15 control samples were examined.Results: The relative expression of hsa-miR-24-3p and hsa-miR-34a-5p was upregulated by 4.4 (p = 0.0001) and 3.8 (p = 0.005) -fold in AP patient's blood plasma compared to control subjects. CYP4F2 enzyme level in blood plasma were 2.1 (p = 0.001) times lower in AP patients. Circulating hsa-miR-24-3p was negatively associated with CYP4F2 enzyme level (Spearman correlation coefficient rank r= -0.32; p = 0.03). Moreover, patients that were taking atorvastatin, had 1.5 (p = 0.04) times higher hsa-miR-24-3p expression in blood plasma.Conclusions. Our data suggest that hsa-miR-24-3p might have an effect on CYP4F2 activity during atherosclerosis.

Biomarkers in Aortic Valve Stenosis and their Clinical Significance in Transcatheter Aortic Valve Implantation

Aortic valve stenosis is one of the most common valvular heart disorders and the prevalence will rise as the population ages. Once symptomatic patients with aortic valve stenosis tend to fare worse with high mortality rates. Aortic valve replacement is indicated in these patients and besides the standard surgical replacement, a less invasive approach, transcatheter aortic valve implantation, has gained momentum and has showed promising and solid results in patients with high surgical risk. An important aspect of evaluating patients with aortic valve stenosis is the ability to choose the best possible candidate for the procedure. In addition, predicting the short and long-term clinical outcomes after the valve replacement could offer the treating physicians a better insight and provide information for optimal therapy. Biomarkers are biological parameters that can be objectively measured and evaluated as indicators of normal biological processes and are easily monitored. The aim of this review is to critically assess some of the most widely used biomarkers at present (natriuretic peptides, troponins, C-reactive protein) and provide an insight in novel biomarkers that are currently being investigated (galectin-3, growth differentiation factor-15, microRNAs) for possible diagnostic and prognostic use in aortic valve stenosis and transcatheter aortic valve implantation respectively.

Plasma miR-22-5p, miR-132-5p, and miR-150-3p Are Associated with Acute Myocardial Infarction

Circulating microRNAs (miRNAs) are potential biomarkers for cardiovascular diseases. Our study aimed to determine whether miR-22-5p, miR-132-5p, and miR-150-3p represent novel biomarkers for acute myocardial infarction (AMI). Plasma samples were isolated from 35 AMI patients and 55 matched controls. Total RNA was extracted, and quantitative real-time PCR and ELISA were performed to investigate the expressions of miRNAs and cardiac troponin I (cTnI), respectively. We found that plasma levels of miR-22-5p and miR-150-3p were significantly higher during the early stage of AMI and their expression levels peaked earlier than cTnI. Conversely, circulating miR-132-5p was sustained at a low level during the early phase of AMI. All three circulating miRNAs were correlated with plasma cTnI levels. A receiver operating characteristic (ROC) analysis suggested that each single miRNA had considerable diagnostic efficacy for AMI. Moreover, combining the three miRNAs improved their diagnostic efficacy. Furthermore, neither heparin nor medications for coronary heart disease (CHD) affected plasma levels of miR-22-5p and miR-132-5p, but circulating miR-150-3p was downregulated by medications for CHD. We concluded that plasma miR-22-5p, miR-132-5p, and miR-150-3p may serve as candidate diagnostic biomarkers for early diagnosis of AMI. Moreover, a panel consisting of these three miRNAs may achieve a higher diagnostic value.

Opportunities for microRNAs in the Crowded Field of Cardiovascular Biomarkers

Cardiovascular diseases exist across all developed countries. Biomarkers that can predict or diagnose diseases early in their pathogeneses can reduce their morbidity and mortality in afflicted individuals. microRNAs are small regulatory RNAs that modulate translation and have been identified as potential fluid-based biomarkers across numerous maladies. We describe the current state of cardiovascular disease biomarkers across a range of diseases, including myocardial infarction, acute coronary syndrome, myocarditis, hypertension, heart failure, heart transplantation, aortic stenosis, diabetic cardiomyopathy, atrial fibrillation, and sepsis. We present the current understanding of microRNAs as possible biomarkers in these categories and where their best opportunities exist to enter clinical practice.

A Hearty Dose of Noncoding RNAs: The Imprinted DLK1-DIO3 Locus in Cardiac Development and Disease

The imprinted Dlk1-Dio3 genomic region harbors a noncoding RNA cluster encoding over fifty microRNAs (miRNAs), three long noncoding RNAs (lncRNAs), and a small nucleolar RNA (snoRNA) gene array. These distinct noncoding RNAs (ncRNAs) are thought to arise from a single polycistronic transcript that is subsequently processed into individual ncRNAs, each with important roles in diverse cellular contexts. Considering these ncRNAs are derived from a polycistron, it is possible that some coordinately regulate discrete biological processes in the heart. Here, we provide a comprehensive summary of Dlk1-Dio3 miRNAs and lncRNAs, as they are currently understood in the cellular and organ-level context of the cardiovascular system. Highlighted are expression profiles, mechanistic contributions, and functional roles of these ncRNAs in heart development and disease. Notably, a number of these ncRNAs are implicated in processes often perturbed in heart disease, including proliferation, differentiation, cell death, and fibrosis. However, most literature falls short of characterizing precise mechanisms for many of these ncRNAs, warranting further investigation. Taken together, the Dlk1-Dio3 locus represents a largely unexplored noncoding regulator of cardiac homeostasis, harboring numerous ncRNAs that may serve as therapeutic targets for cardiovascular disease.

Blood, tissue and imaging biomarkers in calcific aortic valve stenosis: past, present and future

PURPOSE OF REVIEW

Calcific aortic valve stenosis is the most prevalent valvular heart disease in the high-income countries. To this date, no medical therapy has been proven to prevent or to stop the progression of aortic valve stenosis. The physiopathology of aortic valve stenosis is highly complex and involves several signalling pathways, as well as genetic related factors, which delay the elaboration of effective pharmacotherapies. Moreover, it is difficult to predict accurately the progression of the valve stenosis and finding the optimal timing for aortic valve replacement remains challenging. Therefore, the present review makes an inventory of the most recent and promising circulating and imaging biomarkers related to the underlying mechanisms involved in the physiopathology of aortic valve stenosis, as well as the biomarkers associated with the left ventricular (LV) remodelling and subsequent dysfunction in patients with aortic valve stenosis.

RECENT FINDINGS

Over the last decade, several blood, tissue and imaging biomarkers have been investigated in aortic valve stenosis patients. At the aortic valve level, these biomarkers are mostly associated and/or involved with processes such as lipid infiltration and oxidation, chronic inflammation and fibrocalcific remodelling of the valve. Moreover, recent findings suggest that aging and sex hormones might interact with these multiple processes. Several studies demonstrated the usefulness of circulating biomarkers such as lipoprotein(a), brain natriuretic peptides and high-sensitivity cardiac troponin, which are very close to clinical routine. Furthermore, noninvasive imaging biomarkers including positron emission tomography and cardiac magnetic resonance, which provide a detailed view of the disease activity within the aortic valve and its repercussion on the left ventricle, may help to improve the understanding of aortic valve stenosis physiopathology and enhance the risk stratification. Other biomarkers such as von Willebrand factor and microRNAs are promising but further studies are needed to prove their additive value in aortic valve stenosis.

SUMMARY

Most of the biomarkers are used in research and thus, are still being investigated. However, some biomarkers including plasma level of lipoprotein(a), F-sodium fluoride, brain natriuretic peptides and high-sensitivity cardiac troponin can be or are very close to be used for the clinical management of patients with aortic valve stenosis. Moreover, a multibiomarker approach might provide a more global view of the disease activity and improve the management strategies of these patients.

Epigenome alterations in aortic valve stenosis and its related left ventricular hypertrophy

Aortic valve stenosis is the most common cardiac valve disease, and with current trends in the population demographics, its prevalence is likely to rise, thus posing a major health and economic burden facing the worldwide societies. Over the past decade, it has become more than clear that our traditional genetic views do not sufficiently explain the well-known link between AS, proatherogenic risk factors, flow-induced mechanical forces, and disease-prone environmental influences. Recent breakthroughs in the field of epigenetics offer us a new perspective on gene regulation, which has broadened our perspective on etiology of aortic stenosis and other aortic valve diseases. Since all known epigenetic marks are potentially reversible this perspective is especially exciting given the potential for development of successful and non-invasive therapeutic intervention and reprogramming of cells at the epigenetic level even in the early stages of disease progression. This review will examine the known relationships between four major epigenetic mechanisms: DNA methylation, posttranslational histone modification, ATP-dependent chromatin remodeling, and non-coding regulatory RNAs, and initiation and progression of AS. Numerous profiling and functional studies indicate that they could contribute to endothelial dysfunctions, disease-prone activation of monocyte-macrophage and circulatory osteoprogenitor cells and activation and osteogenic transdifferentiation of aortic valve interstitial cells, thus leading to valvular inflammation, fibrosis, and calcification, and to pressure overload-induced maladaptive myocardial remodeling and left ventricular hypertrophy. This is especcialy the case for small non-coding microRNAs but was also, although in a smaller scale, convincingly demonstrated for other members of cellular epigenome landscape. Equally important, and clinically most relevant, the reported data indicate that epigenetic marks, particularly certain microRNA signatures, could represent useful non-invasive biomarkers that reflect the disease progression and patients prognosis for recovery after the valve replacement surgery.

Circulating miR-323-3p is a biomarker for cardiomyopathy and an indicator of phenotypic variability in Friedreich's ataxia patients

MicroRNAs (miRNAs) are noncoding RNAs that contribute to gene expression modulation by regulating important cellular pathways. In this study, we used small RNA sequencing to identify a series of circulating miRNAs in blood samples taken from Friedreich’s ataxia patients. We were thus able to develop a miRNA biomarker signature to differentiate Friedreich’s ataxia (FRDA) patients from healthy people. Most research on FDRA has focused on understanding the role of frataxin in the mitochondria, and a whole molecular view of pathological pathways underlying FRDA therefore remains to be elucidated. We found seven differentially expressed miRNAs, and we propose that these miRNAs represent key mechanisms in the modulation of several signalling pathways that regulate the physiopathology of FRDA. If this is the case, miRNAs can be used to characterize phenotypic variation in FRDA and stratify patients’ risk of cardiomyopathy. In this study, we identify miR-323-3p as a candidate marker for phenotypic differentiation in FRDA patients suffering from cardiomyopathy. We propose the use of dynamic miRNAs as biomarkers for phenotypic characterization and prognosis of FRDA.

MicroRNAs Association in the Cardiac Hypertrophy Secondary to Complex Congenital Heart Disease in Children

Complex congenital heart disease (CHD) affects cardiac blood flow, generating a pressure overload in the compromised ventricles and provoking hypertrophy that over time will induce myocardial dysfunction and cause a potential risk of imminent death. Therefore, the early diagnosis of complex CHD is paramount during the first year of life, with surgical treatment of patients favoring survival. In the present study, we analyzed cardiac tissue and plasma of children with cardiac hypertrophy (CH) secondary to CHD for the expression of 11 miRNAs specific to CH in adults. The results were compared with the miRNA expression patterns in tissue and blood of healthy children. In this way, we determined that miRNAs 1, 18b, 21, 23b, 133a, 195, and 208b constitute the expression profile of the cardiac tissue of children with CHD. Meanwhile, miRNAs 21, 23a, 23b, and 24 can be considered specific biomarkers for the diagnosis of CH in infants with CHD. These results suggest that CH secondary to CHD in children differs in its mechanism from that described for adult hypertrophy, offering a new perspective to study the development of this pathology and to determine the potential of hypertrophic miRNAs to be biomarkers for early CH.

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.

Micro-RNA-21 (biomarker) and global longitudinal strain (functional marker) in detection of myocardial fibrotic burden in severe aortic valve stenosis: a pilot study

Aims

Myocardial fibrosis (MF) is a deleterious consequence of aortic valve stenosis (AVS). Global longitudinal strain (GLS) is a novel left ventricular (LV) functional parameter potentially useful to non-invasively estimate MF. MicroRNAs (miRNAs) are non-coding small ribonucleic acids (RNA) modulating genes function, mainly through RNA degradation. miRNA-21 is a biomarker associated with MF in pressure overload. The aim of the present study was to find an integrated algorithm for detection of MF using a combined approach with both bio- and functional markers.

Methods

Thirty-six patients (75.2 ± 8 y.o.; 63 % Female) with severe AVS and preserved LV ejection fraction (EF), candidate to surgical aortic valve replacement (sAVR) were enrolled. Clinical, bio-humoral evaluation (including plasmatic miRNA-21 collected using specific tubes, PAXgene, for stabilization of peripheral RNA) and a complete echocardiographic study, including GLS and septal strain, were performed before sAVR. Twenty-eight of those patients underwent sAVR and, in 23 of them, an inter-ventricular septum biopsy was performed. Tissues were fixed in formalin and embedded in paraffin. Sections were stained with Hematoxylin and Eosin for histological evaluation and with histochemical Masson trichrome for collagen fibers. The different components were calculated and expressed as micrometers². To evaluate tissue miRNA components, sections 2-μm thick were cut using a microtome blade for each slide. Regression analysis was performed to test association between dependent variable and various predictors included in the model.

Results

Despite a preserved EF (66 ± 11 %), patients presented altered myocardial deformation parameters (GLS −14,02 ± 3.8 %; septal longitudinal strain, SSL −9.63 ± 2.9 %; septal longitudinal strain rate, SL-Sr −0.58 ± 0.17 1/s; Septal Longitudinal early-diastolic strain rate, SL-SrE 0.62 ± 0.32 1/s). The extent of MF showed an inverse association with both GLS and septal longitudinal deformation indices (GLS: R² = 0.30; p = 0.02; SSL: R² = 0.36; p = 0.01; SL-Sr: R² = 0.39; p < 0.001; SL-SrE: R² = 0.35; p = 0.001). miRNA-21 was mainly expressed in fibrous tissue (p < 0.0001). A significant association between MF and plasmatic miRNA-21, alone and weighted for measures of structural (LVMi R² = 0.50; p = 0.0005) and functional (SSL R² = 0.35; p = 0.006) remodeling, was found.

Conclusions

In AVS, MF is associated with alterations of regional and global strain. Plasmatic miRNA-21 is directly related to MF and associated with LV structural and functional impairment.

MicroRNA Expression Signature in Degenerative Aortic Stenosis

Degenerative aortic stenosis, characterized by narrowing of the exit of the left ventricle of the heart, has become the most common valvular heart disease in the elderly. The aim of this study was to investigate the microRNA (miRNA) signature in degenerative AS. Through microarray analysis, we identified the miRNA expression signature in the tissue samples from healthy individuals (n = 4) and patients with degenerative AS (n = 4). Six miRNAs (hsa-miR-193a-3p, hsa-miR-29b-1-5p, hsa-miR-505-5p, hsa-miR-194-5p, hsa-miR-99b-3p, and hsa-miR-200b-3p) were overexpressed and 14 (hsa-miR-3663-3p, hsa-miR-513a-5p, hsa-miR-146b-5p, hsa-miR-1972, hsa-miR-718, hsa-miR-3138, hsa-miR-21-5p, hsa-miR-630, hsa-miR-575, hsa-miR-301a-3p, hsa-miR-636, hsa-miR-34a-3p, hsa-miR-21-3p, and hsa-miR-516a-5p) were downregulated in aortic tissue from AS patients. GeneSpring 13.1 was used to identify potential human miRNA target genes by comparing a 3-way comparison of predictions from TargetScan, PITA, and microRNAorg databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to identify potential pathways and functional annotations associated with AS. Twenty miRNAs were significantly differentially expressed between patients with AS samples and normal controls and identified potential miRNA targets and molecular pathways associated with this morbidity. This study describes the miRNA expression signature in degenerative AS and provides an improved understanding of the molecular pathobiology of this disease.

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.

MicroRNAs in Valvular Heart Diseases: Potential Role as Markers and Actors of Valvular and Cardiac Remodeling

miRNAs are a class of over 5000 noncoding RNAs that regulate more than half of the protein-encoding genes by provoking their degradation or preventing their translation. miRNAs are key regulators of complex biological processes underlying several cardiovascular disorders, including left ventricular hypertrophy, ischemic heart disease, heart failure, hypertension and arrhythmias. Moreover, circulating miRNAs herald promise as biomarkers in acute myocardial infarction and heart failure. In this context, this review gives an overview of studies that suggest that miRNAs could also play a role in valvular heart diseases. This area of research is still at its infancy, and further investigations in large patient cohorts and cellular or animal models are needed to provide strong data. Most studies focused on aortic stenosis, one of the most common valvular diseases in developed countries. Profiling and functional analyses indicate that miRNAs could contribute to activation of aortic valve interstitial cells to a myofibroblast phenotype, leading to valvular fibrosis and calcification, and to pressure overload-induced myocardial remodeling and hypertrophy. Data also indicate that specific miRNA signatures, in combination with clinical and functional imaging parameters, could represent useful biomarkers of disease progression or recovery after aortic valve replacement.

Review in Translational Cardiology: MicroRNAs and Myocardial Fibrosis in Aortic Valve Stenosis, a Deep Insight on Left Ventricular Remodeling

MicroRNAs (miRNAs) are a huge class of noncoding RNAs that regulate protein-encoding genes (degradation/inhibition of translation). miRNAs are nowadays recognized as regulators of biological processes underneath cardiovascular disorders including hypertrophy, ischemia, arrhythmias, and valvular disease. In particular, circulating miRNAs are promising biomarkers of pathology. This review gives an overview of studies in aortic valve stenosis (AS), exclusively considering myocardial remodeling processes. We searched through literature (till September 2016), all studies and reviews involving miRNAs and AS (myocardial compartment). Although at the beginning of a new era, clear evidences exist on the potential diagnostic and prognostic implementation of miRNAs in the clinical setting. In particular, for AS, miRNAs are modulators of myocardial remodeling and hypertrophy. In our experience, here presented in summary, the principal findings of our research were a confirm of the pathophysiological role in AS of miRNA-21, in particular, the interdependence between textural miRNA-21 and fibrogenic stimulus induced by an abnormal left ventricular pressure overload. Moreover, circulating miRNA-21 (biomarker) levels are able to reflect the presence of significant myocardial fibrosis (MF). Thus, the combined evaluation of miRNA-21, a marker of MF, and hypertrophy, together with advanced echocardiographic imaging (two-dimensional speckle tracking), could fulfill many existing gaps, renewing older guidelines paradigms, also allowing a better risk prognostic and diagnostic strategies.