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The use of doxorubicin is associated with an increased risk of acute and long-term cardiomyopathy. Despite the constantly growing number of cancer survivors, little is known about the transcriptional mechanisms which progress in the time leading to a severe cardiac outcome. It is also unclear whether long-term transcriptomic alterations related to doxorubicin use are similar to transcriptomic patterns present in patients suffering from other cardiomyopathies. Here we have sequenced miRNA from total plasma and extracellular vesicles (EVs) from 66 childhood acute lymphoblastic leukemia survivors treated with doxorubicin and 61 healthy controls (254 samples in total). We analyzed processes regulated by differentially expressed miRNA and cross-validated our results with the data of patients with clinically manifested cardiomyopathies. Our analyses indicate that the circulating compartment used for inspection should be selected with particular attention. miRNAs contained within EVs may be particularly informative in terms of cardiomyopathy development and may regulate pathways related to neurotrophin, transforming growth factor beta or epidermal growth factor receptors (ErbB). Among miRNAs differentially expressed in vesicles, which additionally are also most variable between groups, we identified those correlated with echocardiographic parameters, including miR-144-3p and miR-423-3p and respectively for plasma miRNAs: let-7g-5p, miR-16-2-3p. Among these, vesicular miR-144-3p correlates with the highest number of echocardiographic parameters and is also differentially expressed in the circulation of patients with dilated cardiomyopathy. We also show that in ALL survivors' distribution of particular miRNAs, e.g., miR-184 between plasma and EVs is different than in healthy controls. This suggests persistent alterations within the cellular sorting and exporting system.

The use of doxorubicin is associated with an increased risk of acute and long-term cardiomyopathy. Despite that the number of cancer survivors is growing constantly, little is known about the transcriptional mechanisms which progress in time leading to severe cardiac outcome. It is also unclear whether long-term transcriptomic alterations are related to an acute response to doxorubicin. We have sequenced miRNA from total plasma and extracellular vesicles (EVs) from 66 acute lymphoblastic leukemia (ALL) survivors treated with doxorubicin and 61 healthy controls (254 samples in total). We identified 94 and 33 TFs regulating differentially expressed miRNA in plasma and EVs compartments, respectively. For total plasma we found: HEY1, NRF2, HIF1A, NOTCH1, and for EVs: TGFB, ZEB1, ASCL2, PELP1, SIP1, TWIST1. Analysis of the data from patients with dilated and idiopathic cardiomyopathy revealed similarities with our data from EVs, especially in the activity of TFs related to epithelial-to-mesenchymal transition (EMT). To verify if similarities exist between acute and long-term response to doxorubicin, we performed experiments on cultured as well as we studied the role of NRF2, previously considered as an important player in acute response, in transcriptomic network upon doxorubicin treatment). KEGG analysis of miRNA targets for EVs indicates development of cardiomyopathy, whereas among GO process we found terms related to cardiac septum. In vitro experiments revealed that NRF2 is co-regulated with NOTCH effectors from HEY family, with known role in muscle regeneration. NRF2 and doxorubicin treatment contribute also to the dysregulation of TWIST family, important for the process of EMT.

BACKGROUND Left ventricular reverse remodeling (LVRR) determines clinical status and outcomes in dilated cardiomyopathy (DCM). The extent of myocardial fibrosis is connected to the systolic function of the heart. The recent discovery of the contribution of microRNAs (miRs) to the regulation of cardiac remodeling, LVRR and fibrosis warrants exploration. OBJECTIVES The aim of the study was to examine the predictive value of circulating and myocardial miR expression for LVRR in DCM. MATERIAL AND METHODS Seventy consecutive DCM patients (age 48 ±12.1 years, 90% male, ejection fraction (EF) 24.4% ±7.4%) were included in the study. At baseline, all patients underwent clinical assessment, echocardiography, venous blood sampling, and right ventricular endomyocardial biopsy. Circulating and myocardial miRs (miR-21, -26, -29, -30, -133a, and -423) were measured with quantitative real-time polymerase chain reaction (qRT-PCR). LVRR was defined as an increase in EF ≥ 10%, accompanied by a decrease in left ventricle end-diastolic diameter (LVEDd) ≥10% or LVEDd ≤ 33 mm/m2 between baseline and 3-month follow-up. RESULTS At the 3-month follow-up, 4 patients had died and 3 patients had incomplete data. The remaining patients were divided according to the presence of LVRR into LVRR-present (n = 32, 51%) and LVRR-absent (n = 31, 49%) groups. Out of all the circulating and tissue miRs under study, only myocardial expression of miR-133a significantly differed between the LVRR-present and LVRR-absent group (1.22 (0.47-1.90) vs 0.61 (0.25-0.99) ΔCq, respectively, p < 0.01). miR-133a was found to be a significant LVRR predictor in unadjusted (odds ratio (OR) = 2.81 (1.23-6.40), p < 0.05) and adjusted for duration of disease, left ventricle end-diastolic (LVED) volume (LVEDvol), hs-troponin-T, and NT-proBNP (OR = 5.20 (1.13-24.050, p < 0.05) models. CONCLUSIONS From all of the circulating and tissue miRs, only myocardial miR-133a showed increased expression in LVRR-present patients and was found an independent LVRR predictor. This indicates a link between miR-133 and cardiac remodeling in DCM.

Background: The relationship between right ventricle (RV), extracellular matrix (ECM) fibrosis and fibrosis-linked, circulating microRNAs in dilated cardiomyopathy (DCM) is unknown. Aim: The aim of the study was to uncover the associations between serum markers of ECM metabolism and circulating microRNAs with RV morphological and functional parameters. Methods: The study population consisted of 70 consecutive DCM patients (ejection fraction 24.4 ± ± 7.4%). Based on detailed echocardiographic assessment — 15 patients had normal RV, whereas 55 patients had RV dilatation (RVD) and/or RV systolic dysfunction (RVSD). Procollagens type I and III carboxy- and amino-terminal peptides, osteopontin (OPN), TGF1-b1, connective tissue growth factor (CTGF), MMP-2, MMP-9 and TIMP-1 were measured in serum as well as expression of miR-21, miR-26, miR-29, miR-30 and miR-133a. All patients underwent endomyocardial biopsy. Results: Biopsy-proven fibrosis was evenly distributed in two groups. Serum levels of fibrosis markers did not differ between groups. OPN, CTGF, MMP-2, and TIMP-1 correlated with RV parameters. Only miR-133 a was differently expressed in both groups. MiR-21, miR-26, miR-30, and miR-133a cor­related with RV morphological but without functional parameters. Not a single marker of fibrosis was independently associated with RV. MiR-30 was associated with RV impairment in the logistic regression model adjusted for age, sex, body mass index, and disease duration; however, lost its significance in the more comprehensive model. Conclusions: Right ventricle structural and functional abnormalities are common in DCM. ECM fibrosis and serum markers are not associated with RV impairment. The prognostic value of studied microRNAs on RV is limited in DCM.

It is unknown whether fibrosis‐associated microRNAs: miR‐21, miR‐26, miR‐29, miR‐30 and miR‐133a are linked to cardiovascular (CV) outcome. The study evaluated the levels of extracellular matrix (ECM) fibrosis and the prevalence of particular microRNAs in patients with dilated cardiomyopathy (DCM) to investigate any correlation with CV events. Methods: Seventy DCM patients (48 ± 12 years, EF 24.4 ± 7.4%) underwent right ventricular biopsy. The control group was comprised of 7 patients with CAD who underwent CABG and intraoperative biopsy. MicroRNAs were measured in blood and myocardial tissue via qPCR. The end‐point was a combination of CV death and urgent HF hospitalization at the end of 12 months. There were differential levels of circulating and myocardial miR‐26 and miR‐29 as well as myocardial miR‐133a when the DCM and CABG groups were compared. Corresponding circulating and myocardial microRNAs did not correlate with one another. There was no correlation between microRNA and ECM fibrosis. By the end of the 12‐month period of the study, CV death had occurred in 6 patients, and a further 19 patients required urgent HF hospitalization. None of the circulating microRNAs was a predictor of the combined end‐point; however, myocardial miR‐133a was an independent predictor in unadjusted models (HR 1.53; 95% CI 1.14‐2.05; P

Decreased plasma levels of microRNA-223 (miR-223), predominantly of platelet origin, were proposed as a surrogate marker of efficacy of antiplatelet therapy. However, higher on-treatment platelet reactivity was associated with lower plasma miR-223 in patients with coronary artery disease (CAD) on dual antiplatelet therapy (DAPT) including clopidogrel and aspirin. Our aim was to compare plasma miR-223 and platelet reactivity in CAD patients on DAPT with newer P2Y12 antagonists vs. clopidogrel. We studied 21 men with CAD admitted to our centre owing to a non-ST-elevation acute coronary syndrome, and with an uncomplicated hospital course. From the day of admission, the patients were receiving either clopidogrel (n = 11) or prasugrel/ticagrelor (n = 10) in addition to aspirin. Before discharge, miR-223 expression in plasma was estimated by quantitative polymerase chain reaction using the comparative Ct method relative to miR-16 as an endogenous control. Multiple electrode aggregometry was used to assess platelet aggregation in response to adenosine diphosphate (ADP). ADP-induced platelet reactivity was decreased in the patients treated with prasugrel or ticagrelor compared with those on clopidogrel (mean ± SD: 139 ± 71 vs. 313 ± 162 arbitrary units [AU]*min, p = 0.006), due to a more potent antiplatelet activity of the novel P2Y12 antagonists. Consequently, six out of seven patients in the lower tertile of the ADP-induced platelet aggregation were treated with the newer P2Y12 blockers, whereas six out of seven patients in the upper tertile were on clopidogrel. Plasma miR-223 was elevated with decreasing platelet reactivity (Spearman's rho = -0.52; p = 0.015 for trend), being significantly higher in the lower tertile of the ADP-induced platelet aggregation (median [range]: 1.06 [0.25-2.31]) vs. the upper tertile (0.20 [0.13-2.30]) (p = 0.04). In conclusion, our preliminary results argue against the notion of low plasma miR-223 as a marker of platelet responsiveness to DAPT. On the contrary, more potent platelet inhibition associated mainly with newer P2Y12 antagonists appears to coincide with higher miR-223 relative to the subjects with attenuated responsiveness to DAPT.