Plasma miR-208 as a biomarker of myocardial injury

Circulating microRNAs are new and sensitive biomarkers of myocardial infarction

AIMS

Circulating microRNAs (miRNAs) may represent a novel class of biomarkers; therefore, we examined whether acute myocardial infarction (MI) modulates miRNAs plasma levels in humans and mice.

METHODS AND RESULTS

Healthy donors (n = 17) and patients (n = 33) with acute ST-segment elevation MI (STEMI) were evaluated. In one cohort (n = 25), the first plasma sample was obtained 517 ± 309 min after the onset of MI symptoms and after coronary reperfusion with percutaneous coronary intervention (PCI); miR-1, -133a, -133b, and -499-5p were ~15- to 140-fold control, whereas miR-122 and -375 were ~87-90% lower than control; 5 days later, miR-1, -133a, -133b, -499-5p, and -375 were back to baseline, whereas miR-122 remained lower than control through Day 30. In additional patients (n = 8; four treated with thrombolysis and four with PCI), miRNAs and troponin I (TnI) were quantified simultaneously starting 156 ± 72 min after the onset of symptoms and at different times thereafter. Peak miR-1, -133a, and -133b expression and TnI level occurred at a similar time, whereas miR-499-5p exhibited a slower time course. In mice, miRNAs plasma levels and TnI were measured 15 min after coronary ligation and at different times thereafter. The behaviour of miR-1, -133a, -133b, and -499-5p was similar to STEMI patients; further, reciprocal changes in the expression levels of these miRNAs were found in cardiac tissue 3-6 h after coronary ligation. In contrast, miR-122 and -375 exhibited minor changes and no significant modulation. In mice with acute hind-limb ischaemia, there was no increase in the plasma level of the above miRNAs.

CONCLUSION

Acute MI up-regulated miR-1, -133a, -133b, and -499-5p plasma levels, both in humans and mice, whereas miR-122 and -375 were lower than control only in STEMI patients. These miRNAs represent novel biomarkers of cardiac damage.

Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis

INTRODUCTION

MicroRNAs (miRNAs), endogenous small noncoding RNAs regulating the activities of target mRNAs and cellular processes, are present in human plasma in a stable form. In this study, we investigated whether miRNAs are also stably present in synovial fluids and whether plasma and synovial fluid miRNAs could be biomarkers of rheumatoid arthritis (RA) and osteoarthritis (OA).

METHODS

We measured concentrations of miR-16, miR-132, miR-146a, miR-155 and miR-223 in synovial fluid from patients with RA and OA, and those in plasma from RA, OA and healthy controls (HCs) by quantitative reverse transcription-polymerase chain reaction. Furthermore, miRNAs in the conditioned medium of synovial tissues, monolayer fibroblast-like synoviocytes, and mononuclear cells were examined. Correlations between miRNAs and biomarkers or disease activities of RA were statistically examined.

RESULTS

Synovial fluid miRNAs were present and as stable as plasma miRNAs for storage at -20 degrees C and freeze-thawing from -20 degrees C to 4 degrees C. In RA and OA, synovial fluid concentrations of miR-16, miR-132, miR-146a, and miR-223 were significantly lower than their plasma concentrations, and there were no correlation between plasma and synovial fluid miRNAs. Interestingly, synovial tissues, fibroblast-like synoviocytes, and mononuclear cells secreted miRNAs in distinct patterns. The expression patterns of miRNAs in synovial fluid of OA were similar to miRNAs secreted by synovial tissues. Synovial fluid miRNAs of RA were likely to originate from synovial tissues and infiltrating cells. Plasma miR-132 of HC was significantly higher than that of RA or OA with high diagnosability. Synovial fluid concentrations of miR-16, miR-146a miR-155 and miR-223 of RA were significantly higher than those of OA. Plasma miRNAs or ratio of synovial fluid miRNAs to plasma miRNAs, including miR-16 and miR-146a, significantly correlated with tender joint counts and 28-joint Disease Activity Score.

CONCLUSIONS

Plasma miRNAs had distinct patterns from synovial fluid miRNAs, which appeared to originate from synovial tissue. Plasma miR-132 well differentiated HCs from patients with RA or OA, while synovial fluid miRNAs differentiated RA and OA. Furthermore, plasma miRNAs correlated with the disease activities of RA. Thus, synovial fluid and plasma miRNAs have potential as diagnostic biomarkers for RA and OA and as a tool for the analysis of their pathogenesis.

Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis

Introduction

MicroRNAs (miRNAs), endogenous small noncoding RNAs regulating the activities of target mRNAs and cellular processes, are present in human plasma in a stable form. In this study, we investigated whether miRNAs are also stably present in synovial fluids and whether plasma and synovial fluid miRNAs could be biomarkers of rheumatoid arthritis (RA) and osteoarthritis (OA).

Methods

We measured concentrations of miR-16, miR-132, miR-146a, miR-155 and miR-223 in synovial fluid from patients with RA and OA, and those in plasma from RA, OA and healthy controls (HCs) by quantitative reverse transcription-polymerase chain reaction. Furthermore, miRNAs in the conditioned medium of synovial tissues, monolayer fibroblast-like synoviocytes, and mononuclear cells were examined. Correlations between miRNAs and biomarkers or disease activities of RA were statistically examined.

Results

Synovial fluid miRNAs were present and as stable as plasma miRNAs for storage at -20°C and freeze-thawing from -20°C to 4°C. In RA and OA, synovial fluid concentrations of miR-16, miR-132, miR-146a, and miR-223 were significantly lower than their plasma concentrations, and there were no correlation between plasma and synovial fluid miRNAs. Interestingly, synovial tissues, fibroblast-like synoviocytes, and mononuclear cells secreted miRNAs in distinct patterns. The expression patterns of miRNAs in synovial fluid of OA were similar to miRNAs secreted by synovial tissues. Synovial fluid miRNAs of RA were likely to originate from synovial tissues and infiltrating cells. Plasma miR-132 of HC was significantly higher than that of RA or OA with high diagnosability. Synovial fluid concentrations of miR-16, miR-146a miR-155 and miR-223 of RA were significantly higher than those of OA. Plasma miRNAs or ratio of synovial fluid miRNAs to plasma miRNAs, including miR-16 and miR-146a, significantly correlated with tender joint counts and 28-joint Disease Activity Score.

Conclusions

Plasma miRNAs had distinct patterns from synovial fluid miRNAs, which appeared to originate from synovial tissue. Plasma miR-132 well differentiated HCs from patients with RA or OA, while synovial fluid miRNAs differentiated RA and OA. Furthermore, plasma miRNAs correlated with the disease activities of RA. Thus, synovial fluid and plasma miRNAs have potential as diagnostic biomarkers for RA and OA and as a tool for the analysis of their pathogenesis.

A translational study of circulating cell-free microRNA-1 in acute myocardial infarction

miRNAs (microRNAs) participate in many diseases including cardiovascular disease. In contrast with our original hypothesis, miRNAs exist in circulating blood and are relatively stable due to binding with other materials. The aim of the present translational study is to establish a method of determining the absolute amount of an miRNA in blood and to determine the potential applications of circulating cell-free miR-1 (microRNA-1) in AMI (acute myocardial infarction). The results revealed that miR-1 is the most abundant miRNA in the heart and is also a heart- and muscle-specific miRNA. In a cardiac cell necrosis model induced by Triton X-100 in vitro, we found that cardiac miR-1 can be released into the culture medium and is stable at least for 24 h. In a rat model of AMI induced by coronary ligation, we found that serum miR-1 is quickly increased after AMI with a peak at 6 h, in which an increase in miR-1 of over 200-fold was demonstrated. The miR-1 level returned to basal levels at 3 days after AMI. Moreover, the serum miR-1 level in rats with AMI had a strong positive correlation with myocardial infarct size. To verify further the relationship between myocardial size and miR-1 level, an IP (ischaemic preconditioning) model was used. The results showed that IP significantly reduced circulating miR-1 levels and myocardial infract size induced by I/R (ischaemia/reperfusion) injury. Finally, the levels of circulating cell-free miR-1 were significantly increased in patients with AMI and had a positive correlation with serum CK-MB (creatine kinase-MB) levels. In conclusion, the results suggest that serum miR-1 could be a novel sensitive diagnostic biomarker for AMI.

Plasma microRNA 499 as a biomarker of acute myocardial infarction

BACKGROUND

MicroRNAs (miRNAs) are endogenous small RNAs 21-25 nucleotides in length. Recently, we reported that miRNA 208 (miR-208) is produced exclusively in the rat myocardium and that plasma miR-208 is a biomarker of myocardial injury in rats. In the present study, we assessed the hypothesis that plasma concentrations of myocardial-specific miRNAs can be used to diagnose myocardial injury in humans.

METHODS

We used array analysis of miRNA production in various human tissues to identify heart-specific miRNAs. We assessed the plasma concentrations of miR-499 in 14 individuals with acute coronary syndromes, 15 individuals with congestive heart failure, and 10 individuals without cardiovascular diseases. Plasma miR-499 concentrations were measured with a real-time reverse-transcription PCR method that used an artificial small RNA as an internal calibrator.

RESULTS

The miRNA array analysis of various human tissues indicated that miR-499 was produced almost exclusively in the heart. Plasma miR-499 concentrations were measurably increased in all individuals with acute myocardial infarction but were below the limit of detection for all individuals in the other patient groups.

CONCLUSIONS

The plasma concentration of miR-499 may be a useful biomarker of myocardial infarction in humans.

MicroRNAs in cardiovascular diseases: biology and potential clinical applications

Cardiovascular diseases represent one of the major causes for increasing rates of human morbidity and mortality across the world. This reinforces the necessity for the development of novel diagnostics and therapies for the early identification and cure of heart diseases. MicroRNAs are evolutionarily conserved small regulatory non-coding RNAs that regulate the expression of large number of genes. They are involved in several cellular pathophysiological pathways and have been shown to play a significant role in the pathogenesis of many disease states. Recent studies have correlated dysregulated miRNA expressions to diseased hearts and also shown the relevance of miRNA in growth, development, function, and stress responsiveness of the heart. The possibility of exploiting miRNAs to develop diagnostic markers or manipulating them to obtain therapeutic effects is very attractive since they have very specific targets in a particular cellular pathway. In this review we will summarize the role played by miRNAs in the heart and discuss the scope of utilizing miRNA-based strategies in the clinics for the benefit of mankind.

MiR423-5p as a circulating biomarker for heart failure

RATIONALE

Aberrant expression profiles of circulating microRNAs (miRNAs) have been described in various diseases and provide high sensitivity and specificity. We explored circulating miRNAs as potential biomarkers in patients with heart failure (HF).

OBJECTIVE

The goal of this study was to determine whether miRNAs allow to distinguish clinical HF not only from healthy controls but also from non-HF forms of dyspnea.

METHODS AND RESULTS

A miRNA array was performed on plasma of 12 healthy controls and 12 HF patients. From this array, we selected 16 miRNAs for a second clinical study in 39 healthy controls and in 50 cases with reports of dyspnea, of whom 30 were diagnosed with HF and 20 were diagnosed with dyspnea attributable to non-HF-related causes. This revealed that miR423-5p was specifically enriched in blood of HF cases and receiver-operator-characteristics (ROC) curve analysis showed miR423-5p to be a diagnostic predictor of HF, with an area under the curve of 0.91 (P<0.001). Five other miRNAs were elevated in HF cases but also slightly increased in non-HF dyspnea cases.

CONCLUSION

We identify 6 miRNAs that are elevated in patients with HF, among which miR423-5p is most strongly related to the clinical diagnosis of HF. These 6 circulating miRNAs provide attractive candidates as putative biomarkers for HF.

Non-coding RNAs: a key to future personalized molecular therapy?

Continual discoveries on non-coding RNA (ncRNA) have changed the landscape of human genetics and molecular biology. Over the past ten years it has become clear that ncRNAs are involved in many physiological cellular processes and contribute to molecular alterations in pathological conditions. Several classes of ncRNAs, such as small interfering RNAs, microRNAs, PIWI-associated RNAs, small nucleolar RNAs and transcribed ultra-conserved regions, are implicated in cancer, heart diseases, immune disorders, and neurodegenerative and metabolic diseases. ncRNAs have a fundamental role in gene regulation and, given their molecular nature, they are thus both emerging therapeutic targets and innovative intervention tools. Next-generation sequencing technologies (for example SOLiD or Genome Analyzer) are having a substantial role in the high-throughput detection of ncRNAs. Tools for non-invasive diagnostics now include monitoring body fluid concentrations of ncRNAs, and new clinical opportunities include silencing and inhibition of ncRNAs or their replacement and re-activation. Here we review recent progress on our understanding of the biological functions of human ncRNAs and their clinical potential.

Circulating microRNA: a novel potential biomarker for early diagnosis of acute myocardial infarction in humans

AIMS

microRNA (miRNA) is reported to be present in the blood of humans and has been increasingly suggested as a biomarker for diseases. We aim to determine the potential of cardiac-specific miRNAs in circulation to serve as biomarkers for acute myocardial infarction (AMI).

METHODS AND RESULTS

By verifying their tissue expression patterns with real-time polymerase chain reaction (PCR) analysis, muscle-enriched miRNAs (miR-1, miR-133a, and miR-499) and cardiac-specific miR-208a were selected as candidates for this study. With miRNA microarray and real-time PCR analyses, miR-1, miR-133a, and miR-499 were present with very low abundance, and miR-208a was absent in the plasma from healthy people. In the AMI rats, the plasma levels of these miRNAs were significantly increased. Especially, miR-208a in plasma was undetected at 0 h, but was significantly increased to a detectable level as early as 1 h after coronary artery occlusion. Further evaluation of the miRNA levels in plasma from AMI patients (n = 33) demonstrated that all four miRNA levels were substantially higher than those from healthy people (n = 30, P < 0.01), patients with non-AMI coronary heart disease (n = 16, P < 0.01), or patients with other cardiovascular diseases (n = 17, P < 0.01). Notably, miR-208a remained undetectable in non-AMI patients, but was easily detected in 90.9% AMI patients and in 100% AMI patients within 4 h of the onset of symptoms. By receiver operating characteristic curve analysis, among the four miRNAs investigated, miR-208a revealed the higher sensitivity and specificity for diagnosing AMI.

CONCLUSION

Elevated cardiac-specific miR-208a in plasma may be a novel biomarker for early detection of myocardial injury in humans.

microRNA: emerging therapeutic targets in acute ischemic diseases

microRNAs (miRNAs) are 21-23-nucleotide non-protein-coding RNA molecules that act as negative regulators of gene expression, modulating the stability and/or the translational efficiency of target messenger RNAs. This review describes miRNA regulation and function in tissue response to acute ischemia. We focused our attention on a subset of miRNAs that have been found de-regulated in different studies, suggesting that they may represent "master ischemic" miRNAs, playing a pathogenetic role in different components of tissue response to ischemia. First, we analyzed the role of miRNAs in cell response to hypoxia, a crucial component of ischemia, and in angiogenesis. Then, we describe miRNAs role in acute myocardial infarction as much as in hindlimb, cerebral, hepatic and retinal ischemia. The role played by specific miRNAs in the regulation of apoptosis, fibrosis, regeneration and myocardial arrhythmias is illustrated. The identification of specific miRNAs as key regulators of the response to ischemia has opened new clinical avenues. miRNAs may constitute excellent non-invasive disease biomarkers. Furthermore, innovative strategies targeting miRNAs, aimed to reduce the levels of pathogenic or aberrantly expressed miRNAs or to elevate the levels of miRNAs with beneficial functions, have been developed and could be applied in the treatment of ischemic diseases.

[Scanning electron microscopy studies in the detection of apo-B,E receptor activity of the lymphocyte membrane for diagnostic verification of genetically determined disorders of lipid metabolism]

We present a scanning electron microscopic method for determining the quantity of the apo B,E-receptors at the surface of lymphocytes. We used human lymphocytes from venous blood. Gold particles, 50 nm in diameter, were conjugated to the receptors by indirect coupling. We visualized the gold particles by means of an electron microscope (JEM 100 S with scanning attachment ASID). The lymphocytes of control persons and of patients with primary hyperlipoproteinaemias were analysed. Scanning electron microscopic assay of labelled apo-B,E-receptors was shown to allow the rapid and accurate identification of patients with autosomal monogenic hypercholesterolaemia.