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Distinct patterns of circulating microRNAs (miRNAs) were found to be involved in misguided thrombus resolution. Thus, we aimed to investigate dysregulated miRNA signatures during the acute phase of pulmonary embolism (PE) and test their diagnostic and predictive value for future diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH). Microarray screening and subsequent validation in a large patient cohort (n = 177) identified three dysregulated miRNAs as potential biomarkers: circulating miR-29a and miR-720 were significantly upregulated and miR-let7a was significantly downregulated in plasma of patients with PE. In a second validation study equal expression patterns for miR-29a and miR-let7a regarding an acute event of recurrent venous thromboembolism (VTE) or deaths were found. MiR-let7a concentrations significantly correlated with echocardiographic and laboratory parameters indicating right ventricular (RV) dysfunction. Additionally, circulating miR-let7a levels were associated with diagnosis of CTEPH during follow-up. Regarding CTEPH diagnosis, ROC analysis illustrated an AUC of 0.767 (95% CI 0.54-0.99) for miR-let7a. Using logistic regression analysis, a calculated patient-cohort optimized miR-let7a cut-off value derived from ROC analysis of ≥ 11.92 was associated with a 12.8-fold increased risk for CTEPH. Therefore, miR-let7a might serve as a novel biomarker to identify patients with haemodynamic impairment and as a novel predictor for patients at risk for CTEPH., (© 2024. The Author(s).)

Background and Aim: Patients with primary sclerosing cholangitis (PSC) are at high risk for the development of cholangiocarcinoma (CC). Analysis of micro ribonucleic acid (MiRNA) patterns is an evolving research field in biliary pathophysiology with potential value in diagnosis and therapy. Our aim was to evaluate miRNA patterns in serum and bile of patients with PSC and/or CC., Methods: Serum and bile from consecutive patients with PSC (n = 40 (serum), n = 52 (bile)), CC (n = 31 (serum), n = 19 (bile)) and patients with CC complicating PSC (PSC/CC) (n = 12 (bile)) were analyzed in a cross-sectional study between 2009 and 2012. As additional control serum samples from healthy individuals were analyzed (n = 12). The miRNA levels in serum and bile were determined with global miRNA profiling and subsequent miRNA-specific polymerase chain reaction-mediated validation., Results: Serum analysis revealed significant differences for miR-1281 (p = 0.001), miR-126 (p = 0.001), miR-26a (p = 0.001), miR-30b (p = 0.001) and miR-122 (p = 0.034) between patients with PSC and patients with CC. All validated miRNAs were significantly lower in healthy individuals. MiR-412 (p = 0.001), miR-640 (p = 0.001), miR-1537 (p = 0.003) and miR-3189 (p = 0.001) were significantly different between patients with PSC and PSC/CC in bile., Conclusions: Patients with PSC and/or CC have distinct miRNA profiles in serum and bile. Furthermore, miRNA concentrations are different in bile of patients with CC on top of PSC indicating the potential diagnostic value of these miRNAs.

Aims: Osteopontin (OPN) is a multifunctional cytokine critically involved in cardiac fibrosis. However, the underlying mechanisms are unresolved. Non-coding RNAs are powerful regulators of gene expression and thus might mediate this process., Methods and Results: OPN and miR-21 were significantly increased in cardiac biopsies of patients with myocardial fibrosis. Ang II infusion via osmotic minipumps led to specific miRNA regulations with miR-21 being strongly induced in wild-type (WT) but not OPN knockout (KO) mice. This was associated with enhanced cardiac collagen content, myofibroblast activation, ERK-MAP kinase as well as AKT signalling pathway activation and a reduced expression of Phosphatase and Tensin Homologue (PTEN) as well as SMAD7 in WT but not OPN KO mice. In contrast, cardiotropic AAV9-mediated overexpression of OPN in vivo further enhanced cardiac fibrosis. In vitro, Ang II induced expression of miR-21 in WT cardiac fibroblasts, while miR-21 levels were unchanged in OPN KO fibroblasts. As pri-miR-21 was also increased by Ang II, we studied potential involved upstream regulators; Electrophoretic Mobility Shift and Chromatin Immunoprecipitation analyses confirmed activation of the miR-21 upstream-transcription factor AP-1 by Ang II. Recombinant OPN directly activated miR-21, enhanced fibrosis, and activated the phosphoinositide 3-kinase pathway. Locked nucleic acid-mediated miR-21 silencing ameliorated cardiac fibrosis development in vivo., Conclusion: In cardiac fibrosis related to Ang II, miR-21 is transcriptionally activated and targets PTEN/SMAD7 resulting in increased fibroblast survival. OPN KO animals are protected from miR-21 increase and fibrosis development due to impaired AP-1 activation and fibroblast activation., (© The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: Differentiation of heart failure with reduced (HFrEF) or preserved (HFpEF) ejection fraction independent of echocardiography is challenging in the community. Diagnostic strategies based on monitoring circulating microRNA (miRNA) levels may prove to be of clinical value in the near future. The aim of this study was to identify a novel miRNA signature that could be a useful HF diagnostic tool and provide valuable clinical information on whether a patient has HFrEF or HFpEF., Methods and Results: MiRNA biomarker discovery was carried out on three patient cohorts, no heart failure (no-HF), HFrEF, and HFpEF, using Taqman miRNA arrays. The top five miRNA candidates were selected based on differential expression in HFpEF and HFrEF (miR-30c, -146a, -221, -328, and -375), and their expression levels were also different between HF and no-HF. These selected miRNAs were further verified and validated in an independent cohort consisting of 225 patients. The discriminative value of BNP as a HF diagnostic could be improved by use in combination with any of the miRNA candidates alone or in a panel. Combinations of two or more miRNA candidates with BNP had the ability to improve significantly predictive models to distinguish HFpEF from HFrEF compared with using BNP alone (area under the receiver operating characteristic curve >0.82)., Conclusion: This study has shown for the first time that various miRNA combinations are useful biomarkers for HF, and also in the differentiation of HFpEF from HFrEF. The utility of these biomarker combinations can be altered by inclusion of natriuretic peptide. MiRNA biomarkers may support diagnostic strategies in subpopulations of patients with HF., (© 2015 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Atrial fibrosis is important for the pathogenesis of atrial fibrillation (AF) but the underlying signal transduction is incompletely understood. We therefore studied the role of microRNA-21 (miR-21) and its downstream target Sprouty 1 (Spry1) during atrial fibrillation. Left atria (LA) from patients with AF showed a 2.5-fold increased expression of miR-21 compared to matched LA of patients in sinus rhythm. Increased miR-21 expression correlated positively with atrial collagen content and was associated with a reduced protein expression of Spry1 and increased expression of connective tissue growth factor (CTGF), lysyl oxidase and Rac1-GTPase. Neonatal cardiac fibroblasts treated with angiotensin II (AngII) or CTGF showed an increased miR-21 and decreased Spry1 expression. Pretreatment with an inhibitor of Rac1 GTPase, NSC23766, reduced the AngII-induced upregulation of miR-21. A small molecule inhibitor of lysyl oxidase, BAPN, prevented the AngII as well as the CTGF-induced miR-21 expression. Transgenic mice with cardiac overexpression of Rac1, which develop spontaneous AF and atrial fibrosis with increasing age, showed upregulation of miR-21 expression associated with reduced Spry1 expression. miR-21 expression and signalling in vivo were prevented by long-term treatment of the mice with statins. Direct inhibition of miR-21 by antagomir-21 prevented fibrosis of the atrial myocardium post-myocardial infarction. Left atria of patients with atrial fibrillation are characterized by upregulation of miR-21 und reduced expression of Spry1. Activation of Rac1 by angiotensin II leads to a CTGF- and lysyl oxidase-mediated increase of miR-21 expression contributing to structural remodelling of the atrial myocardium.

Pathological growth of cardiomyocytes (hypertrophy) is a major determinant for the development of heart failure, one of the leading medical causes of mortality worldwide. Here we show that the microRNA (miRNA)-212/132 family regulates cardiac hypertrophy and autophagy in cardiomyocytes. Hypertrophic stimuli upregulate cardiomyocyte expression of miR-212 and miR-132, which are both necessary and sufficient to drive the hypertrophic growth of cardiomyocytes. MiR-212/132 null mice are protected from pressure-overload-induced heart failure, whereas cardiomyocyte-specific overexpression of the miR-212/132 family leads to pathological cardiac hypertrophy, heart failure and death in mice. Both miR-212 and miR-132 directly target the anti-hypertrophic and pro-autophagic FoxO3 transcription factor and overexpression of these miRNAs leads to hyperactivation of pro-hypertrophic calcineurin/NFAT signalling and an impaired autophagic response upon starvation. Pharmacological inhibition of miR-132 by antagomir injection rescues cardiac hypertrophy and heart failure in mice, offering a possible therapeutic approach for cardiac failure.

Circulating microRNAs may have diagnostic potential in acute coronary syndrome (ACS). Previous studies, however, were based on low patient numbers and could not assess the relation of microRNAs to clinical characteristics and their potential prognostic value. We thus assessed the diagnostic and prognostic value of cardiomyocyte-enriched microRNAs in the context of clinical variables and a sensitive myonecrosis biomarker in a larger ACS cohort. MiR-1, miR-133a, miR-133b, miR-208a, miR-208b, and miR-499 concentrations were measured by quantitative reverse transcription PCR in plasma samples obtained on admission from 444 patients with ACS. High-sensitivity troponin T (hsTnT) was measured by immunoassay. Patients were followed for 6 months regarding all-cause mortality. In a multiple linear regression analysis that included clinical variables and hsTnT, miR-1, miR-133a, miR-133b, and miR-208b were independently associated with hsTnT levels (all P<0.001). Patients with myocardial infarction presented with higher levels of miR-1, miR-133a, and miR-208b compared with patients with unstable angina. However, all six investigated microRNAs showed a large overlap between patients with unstable angina or myocardial infarction. MiR-133a and miR-208b levels were significantly associated with the risk of death in univariate and age- and gender-adjusted analyses. Both microRNAs lost their independent association with outcome upon further adjustment for hsTnT. The present study tempers speculations about the potential usefulness of cardiomyocyte-enriched microRNAs as diagnostic or prognostic markers in ACS., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Myocardial infarction leads to cardiac remodeling and development of heart failure. Insufficient myocardial capillary density after myocardial infarction has been identified as a critical event in this process, although the underlying mechanisms of cardiac angiogenesis are mechanistically not well understood., Methods and Results: Here, we show that the small noncoding RNA microRNA-24 (miR-24) is enriched in cardiac endothelial cells and considerably upregulated after cardiac ischemia. MiR-24 induces endothelial cell apoptosis, abolishes endothelial capillary network formation on Matrigel, and inhibits cell sprouting from endothelial spheroids. These effects are mediated through targeting of the endothelium-enriched transcription factor GATA2 and the p21-activated kinase PAK4, which were identified by bioinformatic predictions and validated by luciferase gene reporter assays. Respective downstream signaling cascades involving phosphorylated BAD (Bcl-XL/Bcl-2-associated death promoter) and Sirtuin1 were identified by transcriptome, protein arrays, and chromatin immunoprecipitation analyses. Overexpression of miR-24 or silencing of its targets significantly impaired angiogenesis in zebrafish embryos. Blocking of endothelial miR-24 limited myocardial infarct size of mice via prevention of endothelial apoptosis and enhancement of vascularity, which led to preserved cardiac function and survival., Conclusions: Our findings indicate that miR-24 acts as a critical regulator of endothelial cell apoptosis and angiogenesis and is suitable for therapeutic intervention in the setting of ischemic heart disease.

Background and Objectives: MicroRNAs (miRNAs) are small ribonucleotides regulating gene expression. MicroRNAs are present in the blood in a remarkably stable form. We tested whether circulating miRNAs in the plasma of critically ill patients with acute kidney injury (AKI) at the inception of renal replacement therapy are deregulated and may predict survival., Design, Setting, Participants, & Measurements: We profiled miRNAs using RNA isolated from the plasma of patients with AKI and healthy controls. The results were validated in 77 patients with acute kidney injury, 30 age-matched healthy controls, and 18 critically ill patients with acute myocardial infarction by quantitative real-time PCR., Results: Circulating levels of miR-16 and miR-320 were downregulated in the plasma of kidney injury AKI patients, whereas miR-210 was upregulated compared with healthy controls (all P < 0.0001) and disease controls (miR-210 and miR-16: P < 0.0001; miR-320: P = 0.03). Cox regression (P < 0.05) and Kaplan-Meier curve analysis (P = 0.03) revealed miR-210 as an independent and powerful predictor of 28-day survival., Conclusions: Circulating miRNAs are altered in patients with kidney injury AKI. MiR-210 predicts mortality in this patient cohort and may serve as a novel biomarker AKI reflecting pathophysiological changes on a cellular level.

Rationale: The endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) is increased in patients with coronary artery disease and may regulate function of circulating angiogenic progenitor cells (APCs) by small regulatory RNAs., Objectives: To study the role of microRNAs in ADMA-mediated impairment of APCs., Methods and Results: By using microarray analyses, we established microRNA expression profiles of human APCs. We used ADMA to induce APC dysfunction and found 16 deregulated microRNAs. We focused on miR-21, which was 3-fold upregulated by ADMA treatment. Overexpression of miR-21 in human APCs impaired migratory capacity. To identify regulated miR-21 targets, we used proteome analysis, using difference in-gel electrophoresis followed by mass spectrometric analysis of regulated proteins. We found that transfection of miR-21 precursors significantly repressed superoxide dismutase 2 in APCs, which resulted in increased intracellular reactive oxygen species concentration and impaired nitric oxide bioavailability. MiR-21 further repressed sprouty-2, leading to Erk Map kinase-dependent reactive oxygen species formation and APC migratory defects. Small interference RNA-mediated superoxide dismutase 2 or sprouty-2 reduction also increased reactive oxygen species formation and impaired APC migratory capacity. ADMA-mediated reactive oxygen species formation and APC dysfunction was rescued by miR-21 blockade. APCs from patients with coronary artery disease and high ADMA plasma levels displayed >4-fold elevated miR-21 levels, low superoxide dismutase 2 expression, and impaired migratory capacity, which could be normalized by miR-21 antagonism., Conclusions: We identified a novel miR-21-dependent mechanism of ADMA-mediated APC dysfunction. MiR-21 antagonism therefore emerges as an interesting strategy to improve dysfunctional APCs in patients with coronary artery disease.

The article discusses a research study which investigated the role of microRNA in asymmetrical dimethylarginine (ADMA)-mediated impairment of angiogenic progenitor cells (APC). A review of the related literature on ADMA is given. It briefly describes the methods employed by the research authors. Findings of the study demonstrated that transfection of miR-21 precursors significantly suppressed superoxide dismutase 2 in APC, and that patients with coronary artery disease have an elevated ADMA plasma levels.