Development Of Myocardial Fibrosis Research Articles

DNMT1 methylation of LncRNA-ANRIL causes myocardial fibrosis pyroptosis by interfering with the NLRP3/Caspase-1 pathway.

Myocardial fibrosis is a common pathological manifestation that occurs in various cardiac diseases. The present investigation aims to reveal how DNMT1/lncRNA-ANRIL/NLRP3 influences fibrosis and cardiac fibroblast pyroptosis. Here, we used ISO to induce myocardial fibrosis in mice, and LPS and ATP to induce myocardial fibroblast pyroptosis. The results showed that DNMT1, Caspase-1, and NLRP3 expression were significantly increased in fibrotic murine myocardium and pyroptotic cardiac fibroblasts, whereas LncRNA-ANRIL expression was decreased. DNMT1 overexpression decreased the level of LncRNA-ANRIL while increasing the levels of NLRP3 and Caspase-1. Contrarily, silencing DNMT1 increased the LncRNA-ANRIL and decreased the levels of NLRP3 and Caspase-1. Silencing LncRNA-ANRIL increased the levels of NLRP3 and Caspase-1. The present findings suggest that DNMT1 can methylate LncRNA-ANRIL during the development of myocardial fibrosis and CFs cell scorching, resulting in low LncRNA-ANRIL expression, thereby influencing myocardial fibrosis and cardiac fibroblast pyroptosis.

Non-coding RNAs: targets for Chinese herbal medicine in treating myocardial fibrosis.

Cardiovascular diseases have become the leading cause of death in urban and rural areas. Myocardial fibrosis is a common pathological manifestation at the adaptive and repair stage of cardiovascular diseases, easily predisposing to cardiac death. Non-coding RNAs (ncRNAs), RNA molecules with no coding potential, can regulate gene expression in the occurrence and development of myocardial fibrosis. Recent studies have suggested that Chinese herbal medicine can relieve myocardial fibrosis through targeting various ncRNAs, mainly including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Thus, ncRNAs are novel drug targets for Chinese herbal medicine. Herein, we summarized the current understanding of ncRNAs in the pathogenesis of myocardial fibrosis, and highlighted the contribution of ncRNAs to the therapeutic effect of Chinese herbal medicine on myocardial fibrosis. Further, we discussed the future directions regarding the potential applications of ncRNA-based drug screening platform to screen drugs for myocardial fibrosis.

Coronary Microvascular Dysfunction and Diffuse Myocardial Fibrosis in Patients With Type 2 Diabetes Using Quantitative Perfusion MRI.

Imaging techniques that quantitatively and automatically measure changes in the myocardial microcirculation in patients with diabetes are lacking. To detect diabetic myocardial microvascular complications using a novel automatic quantitative perfusion MRI technique, and to explore the relationship between myocardial microcirculation dysfunction and fibrosis. Prospective. 101 patients with type 2 diabetes mellitus (T2DM) (53 without and 48 with complications), 20 healthy volunteers. 3.0T; modified Look-Locker inversion-recovery sequence; saturation recovery sequence and dual-bolus technique; segmented fast low-angle shot sequence. All participants underwent MRI to determine the rest myocardial blood flow (MBF), stress MBF, myocardial perfusion reserve (MPR), and extracellular volume (ECV), which represents the extent of myocardial fibrosis. Kolmogorov-Smirnov test, Shapiro-Wilk test, Kruskal-Wallis H test, Mann-Whitney U test, chi-square test, Spearman correlation coefficient, multivariable linear regression analysis. P < 0.05 was considered statistically significant. The rest MBF was not significantly different between the T2DM without complications group (1.1, IQR: 0.9-1.3) and the control group (1.1, 1.0-1.3) (P = 1.000), but it was significantly lower in the T2DM with complications group (0.8, 0.6-1.0) than in both other groups. The stress MBF and MPR were significantly lower in the T2DM without complications group (1.9, 1.5-2.3, and 1.7, 1.4-2.1, respectively) than in the control group (3.0, 2.6-3.5, and 2.7, 2.4-3.1, respectively), and were also significantly lower in the T2DM with complications group (1.1, 0.9-1.4, and 1.4, 1.2-1.8, respectively) than in the T2DM without complications group. A decrease in MBF and MPR were significantly associated with an increase in the ECV. Quantitative perfusion MRI can evaluate myocardial microcirculation dysfunction. In T2DM, there was a significant decrease in both MBF and MPR compared to healthy controls, with the decrease being significantly different between T2DM with and without complications groups. The decrease of MBF was significantly associated with the development of myocardial fibrosis, as determined by ECV. 2 TECHNICAL EFFICACY: Stage 3.

Modulation of myocardial inflammation, fibrosis development and ventricular arrhythmogenicity by endurance exercise in murine coxsackievirus B3 myocarditis

Abstract Aims Nonischaemic myocardial fibrosis is associated with progressive deterioration of myocardial function and forms the substrate for arrhythmias in atria and ventricles. In the absence of a specific aetiology, its origin is commonly attributed to preceding viral myocarditis. Athletes presenting with ventricular arrhythmias often demonstrate nonischaemic fibrosis on magnetic resonance imaging. Previous translational studies have shown an adverse effect of exercise on the course of acute viral myocarditis. Nevertheless, the effect on myocardial fibrosis development, a frequent and important consequence of viral myocarditis, has not yet been investigated. In the present study, we evaluate for the first time the impact of endurance exercise on longer-term myocardial inflammation, myocardial fibrosis and arrhythmogenicity using a murine viral myocarditis model. Methods and results Male C57BL/6J mice (11 weeks of age, n=72) were randomly assigned to 8 weeks of treadmill running (EEX) or without exercise (SED). Two weeks into the study (training or control), animals were injected intraperitoneally with either coxsackievirus B3 to induce acute viral myocarditis (CVB) or vehicle (PBS). Exercising myocarditis mice showed lower mortality (11% vs. 27%), albeit without statistical significance (P=0.23). At sacrifice (i.e. 6 weeks after inoculation), prominent myocardial inflammatory infiltration and cardiomyocyte loss was observed in both CVB groups, without difference on semiquantitative histological scoring. Nevertheless, the infiltrating cells in the CVB-EEX group were more often proinflammatory in nature (predominantly iNOS-reactive macrophages and positive CD8+/CD4+ ratio) compared to these in CVB-SED (predominantly arginase-1-reactive macrophages and higher CD4+/CD8+ ratio). In addition, the EEX group showed more haemosiderin-laden macrophages and spindled fibroblasts as signs of organisation. At that time, the majority of virus was cleared from the heart. Treadmill running during myocarditis enhanced development of interstitial fibrosis (with limited or extensive distribution)(82.4% in CVB-EEX vs. 56.3% in CVB-SED; P=0.049) and perivascular and/or interstitial fibrosis with extensive distribution (64.7% &amp; 64.7% in CVB-EEX vs. 50% &amp; 31.3% in CVB-SED; P=0.048). The highest scar counts were observed in CVB-EEX, but the mean count (1.9 vs. 1.2; P=0.19) did not significantly differ between the myocarditis groups. In CVB-EEX, the lesions contained denser and more organised collagen bundles. In vivo electrophysiology studies showed similar ventricular arrhythmia inducibility (P&amp;gt;0.20) and arrhythmia burden (P=0.49) in the myocarditis groups, although the longest arrhythmias and highest cumulative burden occurred in CVB-EEX. Conclusion Endurance exercise training during viral myocarditis modulates the longer-term inflammatory process and promotes perivascular and interstitial fibrosis development, potentially enhancing ventricular arrhythmogenicity.

TNFSF14/LIGHT promotes cardiac fibrosis and atrial fibrillation vulnerability via PI3Kγ/SGK1 pathway-dependent M2 macrophage polarisation

BackgroundTumour necrosis factor superfamily protein 14 (TNFSF14), also called LIGHT, is an important regulator of immunological and fibrosis diseases. However, its specific involvement in cardiac fibrosis and atrial fibrillation (AF) has not been fully elucidated. The objective of this study is to examine the influence of LIGHT on the development of myocardial fibrosis and AF.MethodsPCR arrays of peripheral blood mononuclear cells (PBMCs) from patients with AF and sinus rhythm was used to identify the dominant differentially expressed genes, followed by ELISA to evaluate its serum protein levels. Morphological, functional, and electrophysiological changes in the heart were detected in vivo after the tail intravenous injection of recombinant LIGHT (rLIGHT) in mice for 4 weeks. rLIGHT was used to stimulate bone marrow-derived macrophages (BMDMs) to prepare a macrophage-conditioned medium (MCM) in vitro. Then, the MCM was used to culture mouse cardiac fibroblasts (CFs). The expression of relevant proteins and genes was determined using qRT-PCR, western blotting, and immunostaining.ResultsThe mRNA levels of LIGHT and TNFRSF14 were higher in the PBMCs of patients with AF than in those of the healthy controls. Additionally, the serum protein levels of LIGHT were higher in patients with AF than those in the healthy controls and were correlated with left atrial reverse remodelling. Furthermore, we demonstrated that rLIGHT injection promoted macrophage infiltration and M2 polarisation in the heart, in addition to promoting atrial fibrosis and AF inducibility in vivo, as detected with MASSON staining and atrial burst pacing respectively. RNA sequencing of heart samples revealed that the PI3Kγ/SGK1 pathway may participate in these pathological processes. Therefore, we confirmed the hypothesis that rLIGHT promotes BMDM M2 polarisation and TGB-β1 secretion, and that this process can be inhibited by PI3Kγ and SGK1 inhibitors in vitro. Meanwhile, increased collagen synthesis and myofibroblast transition were observed in LIGHT-stimulated MCM-cultured CFs and were ameliorated in the groups treated with PI3Kγ and SGK1 inhibitors.ConclusionLIGHT protein levels in peripheral blood can be used as a prognostic marker for AF and to evaluate its severity. LIGHT promotes cardiac fibrosis and AF inducibility by promoting macrophage M2 polarisation, wherein PI3Kγ and SGK1 activation is indispensable.

Abstract P1049: The Impact Of Endurance Exercise On Longer-term Myocardial Fibrosis Development And Ventricular Arrhythmogenicity In Murine Coxsackievirus B3 Myocarditis

Aims: Diagnostic work-up of athletes often reveals nonischaemic myocardial fibrosis, which is associated with cardiac dysfunction and malignant arrhythmias. Its isolated finding on magnetic resonance imaging is commonly attributed to preceding viral myocarditis. Previous murine studies have shown a negative effect of exercise early in the course of viral myocarditis. In this study, we investigate, for the first time, the impact of endurance exercise on myocardial fibrosis development and arrhythmogenicity in a murine viral myocarditis model. Methods &amp; Results: Eleven-week-old male C57BL/6J mice (n=72) were randomised to 8 weeks of treadmill running (EEX) or without exercise (SED). After 2 weeks, animals received a single injection with either coxsackievirus B3 to induce acute viral myocarditis (CVB) or vehicle as control (PBS). Exercise resulted in a milder clinical disease course, with less weight loss and better preserved running capacity. In addition, mortality was lower in exercising myocarditis mice (11 vs. 27%), however without statistical significance (P=0.23). Exercise during myocarditis increased the occurrence of interstitial fibrosis (limited or extensive distribution) at sacrifice ( i.e. 6 weeks after inoculation)(82.4% in CVB-EEX vs. 56.3% in CVB-SED; P=0.049). Additionally, exercise enhanced development of perivascular and/or interstitial fibrosis with extensive distribution (64.7% &amp; 64.7% in CVB-EEX vs. 50% &amp; 31.3% in CVB-SED; P=0.048). CVB-EEX animals demonstrated more myocardial scars on average, albeit not significantly (1.9 vs. 1.2; P=0.19), with similar scar distribution. Despite manifest fibrotic remodelling, collagen and fibrogenetic genes were not upregulated in the myocarditis groups at the time of sacrifice. In vivo right ventricular programmed electrical stimulation showed comparable ventricular arrhythmia inducibility in the myocarditis groups (P&gt;0.20). The longest arrhythmias and highest cumulative arrhythmia burden occurred in CVB-EEX, however, without reaching statistical significance when compared to CVB-SED (P=0.49). Conclusion: Endurance exercise during viral myocarditis enhances perivascular and interstitial fibrosis development, which may promote ventricular arrhythmogenicity.

Evaluation of diastolic dysfunction in children with hypertrophic cardiomyopathy and its relationship with development of myocardial fibrosis

BackgroundPatients with hypertrophic cardiomyopathy may develop symptoms of shortness of breathing due to diastolic dysfunction which is not related to the severity of left ventricular outflow tract obstruction. As these patients usually develop a non-ischemic pattern of myocardial fibrosis, this may represent a mechanism for increased myocardial stiffness leading to impaired diastolic filling. The study aimed to determine the prevalence of myocardial fibrosis assessed by magnetic resonance imaging in children with hypertrophic cardiomyopathy and to evaluate its relationship with echocardiographic parameters including left ventricle diastolic dysfunction and to find echocardiographic indices which correlates with myocardial fibrosis as detected by cardiac magnetic resonance. A cross-sectional study was done for data of 50 children with hypertrophic cardiomyopathy from July 2018 to July 2021, patients were divided into (group 1) having myocardial fibrosis and (group 2) with no myocardial fibrosis, and results of echocardiographic parameters were compared between the two groups.ResultsResults showed strong relationship between presence of myocardial fibrosis and each of the following: Interventricular septum thickness, lower lateral and septal early diastolic tissue velocities (E′), E/E′ ratio, presence of left ventricular out flow tract obstruction and the grade of diastolic dysfunction.ConclusionsThe trans-mitral lateral and septal E/E′ (early mitral inflow to early diastolic mitral annular velocity ratio) allows early detection of left ventricular diastolic dysfunction in children with hypertrophic cardiomyopathy. The prevalence of diastolic dysfunction is higher in obstructive hypertrophic cardiomyopathy. The diastolic dysfunction severity is higher in patients with myocardial fibrosis.

Association between myocardial oxygenation and fibrosis in Duchenne Muscular Dystrophy: analysis by oxygenation-sensitive and T1 mapping cardiovascular magnetic resonance (P7-9.002)

<h3>Objective:</h3> To explore whether myocardial hypoxia exists in DMD patients and whether an association exists between regional myocardial oxygenation and fibrosis, using oxygenation-sensitive cardiovascular magnetic resonance and native T1 mapping. <h3>Background:</h3> Myocardial hypoxia is common in many cardiomyopathies and has been proven to be closely related to the occurrence and development of myocardial fibrosis. However, limited studies are available on the relationship between myocardial oxygenation and fibrosis in DMD patients using oxygenation-sensitive magnetic resonance, and whether myocardium hypoxia exists in DMD patients and its underlying relationship with fibrosis in DMD remains unclear. <h3>Design/Methods:</h3> In this prospective study, 91 DMD patients and 30 volunteers underwent CMR. The correlation between oxygenation SI and native T1 value was assessed by Pearson or Spearman correlation coefficients and the association between oxygenation SI and LGE was analyzed by logistic regression. The survival curves were generated by the Kaplan–Meier analysis and compared by the log-rank test. <h3>Results:</h3> In LGE-patients, the oxygenation SI of all segments except the septal segments was significantly decreased than those of the controls. Inferolateral SI and anterolateral SI were weakly correlated with native T1 values. As for LGE+ patients, a further and significant reduction in oxygenation SI was observed relative to the controls. SI was moderately correlated with native T1 values in both negative and positive segments. Multivariable regression modeling indicated inferolateral SI independently associated with LGE. At an average follow-up of 18.63 months, 31 patients experienced progress of LGE. Patients with reduced inferolateral SI were more likely to have an exacerbation of fibrosis. <h3>Conclusions:</h3> Analysis of OS-CMR and native T1 mapping revealed that myocardial hypoxia is common and related to the onset of myocardial fibrosis in DMD patients. And myocardial oxygenation by OS-CMR might be used as the quantitative imaging biomarker for the assessment of myocardial damage and prediction of fibrosis progression in DMD patients. <b>Disclosure:</b> Ms. Zhou has nothing to disclose.

Bioinformatics prediction and experimental verification of a novel microRNA for myocardial fibrosis after myocardial infarction in rats.

MicroRNAs (miRNAs) are endogenous noncoding single-stranded small RNAs. Numerous studies have shown that miRNAs have pivotal roles in the occurrence and development of myocardial fibrosis (MF). However, miRNA expression profile in rats with MF after myocardial infarction (MI) is not well understood. The present study aimed to find the potential miRNA for MF post MI. SPF male Sprague-Dawley (SD) rat models of acute myocardial infarction (AMI) were established by ligating the anterior descending branch of the left coronary artery, while sham-operated rats were only threaded without ligation as a control group. Hematoxylin-eosin and Masson trichrome staining were used to detect myocardial histopathological changes for model evaluation. The differentially expressed miRNAs were detected by using the Agilent Rat miRNA gene chip in the myocardial tissue of the infarct marginal zone. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed by DAVID. The expression of miR-199a-5p was verified by real-time fluorescence quantitative PCR (qRT-PCR). Transfected miR-199a-5p mimics into cardiac fibroblasts (CFs) to construct cell models of miR-199a-5p overexpression. Dual-luciferase reporter assay was employed to validate the target gene of miR-199a-5p. The protein expression of the target gene in CFs transfected with miR-199a-5p mimics were detected by Western blot. Myocardial fibrosis was exacerbated in the model group compared with the control group. Thirteen differentially expressed miRNAs between the two groups were screened and their expression levels in the model group were all higher than those in the control group. The expression of miR-199a-5p was significantly increased in the model group in qRT-PCR, which was consistent with the results of the gene chip. KEGG enrichment analysis showed that the target genes of miR-199a-5p were enriched in the insulin signaling pathway. Furthermore, dual-luciferase reporter assay indicated that miR-199a-5p could negatively regulate the expression of GSK-3β. After transfection, the expression of miR-199a-5p was increased in the miR-199a-5p mimics group. The protein expression of GSK-3β was decreased in CFs transfected with miR-199a-5p mimics. Our study identified miR-199a-5p could promote the progression of myocardial fibrosis after myocardial infarction by targeting GSK-3β, which provides novel targets for diagnosis and treatment of MF.

AMPK/Sirt1-mediated inflammation is positively correlated with myocardial fibrosis during ageing

Objectives Cardiovascular disease is the leading cause of death in the world, and it increases dramatically with ageing. The objective of this study was to elucidate age-dependent molecular changes of inflammation and its correlation with the progression of myocardial fibrosis. Methods Methods: Male SD rats aged 3, 6, 9 and 24 months were used in this study. H&E staining was used to assessed histo-morphological changes in different ages. Masson’s trichrome staining was used to evaluate myocardial fibrosis. Immunofluorescence as well as western blot was carried out to detect the expression of vimentin. Real-time PCR was used to detect the level of pro-inflammatory chemokines MCP-1, IL1β, TNFα and IL-6. Western blotting was also carried out to detect p-AMPK, Sirt1, AC-NF-κB expression. Results Myocardial pathological changes and fibrosis are positively correlated with age. Ageing rats showed an enhanced expression of inflammatory factors and the activation of cardiac fibroblasts increases. Meanwhile, the expression of p-AMPK, Sirt1 and downstream AC-NF-κB increased significantly during ageing. Furthermore, the 15–24 months of age in rats is the fastest changing stage of increased inflammation and decreased Sirt1 activity. Conclusions Ageing is an independent risk factor for the occurrence and development of myocardial fibrosis. During ageing, myocardial fibroblasts are activated, accompanied by an increase in extracellular matrix deposition. The inflammation mediated by AMPK/Sirt1/NF-κB signalling pathway is closely positively correlated with the activation of myocardial fibroblasts and the progression of myocardial fibrosis.

The effect of Endocrine disrupting chemicals on myocardial fibrosis and related mechanism

Endocrine-disrupting chemicals (EDCs) an exogenous agent that interferes with the synthesis, secretion, transport, binding, action, or can mimic the occurrence of natural hormones that damage for the balance of homeostasis. Exposure to EDCs results in damage to human health that may persist in the long term. In recent years, accumulative evidence has demonstrated that EDCs also play a pivotal role in the onset and development of myocardial fibrosis, including heart failure, hypertension and vascular stiffening. Studies indicate that EDCs plays the negative effects of the cardiovascular system, however, EDCs-induced toxicity on heart remains unclear. This review summarized EDCs-induced myocardial fibrosis, and discuss the possible mechanisms of myocardial fibrosis induced by EDCs. This paper could provide further understandings for prevention, diagnosis and treatment of myocardial fibrosis.

ХАРАКТЕРИСТИКА СОСТОЯНИЯ МИОКАРДА И ПРОФИБРОТИЧЕСКИХ ФАКТОРОВ ПРИ РАЗВИТИИ ГИПЕРТОНИЧЕСКОГО СЕРДЦА

Introduction. Myocardial damage caused by arterial hypertension is manifested by changes in myocardial geometry and mass, as well as increased content of collagen and fibrous tissue in the myocardium. Excessive accumulation of collagen in myocardium is the result of imbalance between proteolytic enzymes such as matrix metalloproteinases 1 (MMP-1) and tissue inhibitors of matrix metalloproteinase 1 (TIMMP-1), high content of transforming growth factor β1 (TFG-β1), which was found in fibroblasts and macrophages. Aim. The aim of the study was to investigate the role of MMP-1 activation, its tissue inhibitor TIMMP-1 and TGF-β1 in blood in the development of myocardial fibrosis in locomotive train workers with arterial hypertension. Material and methods. 82 patients with arterial hypertension and 20 virtually healthy control subjects were examined. The patients of the analyzed groups underwent evaluation of the data of daily blood pressure monitoring, echocardiographic examination, based on which the types of left ventricular remodeling, the content of matrix metalloproteinase 1 and its tissue inhibitor activity, the level of transforming growth factor β1 in blood serum were identified. Calculation of the volume fraction of interstitial collagen was performed. Results and discussion. The study established statistically significant signs of structural changes in the left ventricular myocardium, which primarily indicated its marked left ventricular hypertrophy against the background of arterial hypertension due to chronic pressure overload. Statistically significant increase of all levels of serum markers of collagen metabolism was revealed in patients with arterial hypertension in comparison with the control group. Patients with arterial hypertension have a restructuring of the intercellular matrix components and imbalance in the MMP-1/TIMMP-1 system characterized by a shift of the collagen balance towards fibrosis (increase of THF-β1, TIMMP-1 level, decrease of MMP-1/TIMMP-1 52 ВЕСТНИК СОВРЕМЕННОЙ КЛИНИЧЕСКОЙ МЕДИЦИНЫ 2021 Том 14, вып. 6ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ ratio and increase of interstitial collagen volume fraction). Significant increase of interstitial collagen volume fraction index in the group of patients with arterial hypertension comparing to the control group also indirectly indicates high intensity of interstitial collagen genesis in myocardium of these patients. Conclusion. In arterial hypertension, serum levels of THF-β1, MMP-1, and TIMMP-1 increase, which indirectly indicates an increase in myocardial collagen content.

Study on the Relationship between Cardiomyocyte Apoptosis and Left Ventricular Function in Spontaneously Hypertensive Rats

At present, hypertension is a relatively common cardiovascular disease. It not only affects the normal operation of target organs such as the heart and kidneys, but also causes cardiovascular and cerebrovascular diseases, which can lead to death. The apoptosis of cardiomyocytes is widespread in the cardiovascular system and is closely related to vascular diseases. Therefore, the purpose of this article is to explore the relationship between changes in left ventricular function, myocardial multidimensional strain and interstitial fibrosis in spontaneously hypertensive rats (SHR) during cardiomyocyte apoptosis. Whether the research is consistent in terms of order, as the age of hypertensive rats increases, whether there is a close connection between myocardial cell apoptosis and the structure and function of the left heart. The method in this article is to use the method of experimental comparison to randomly group 60 experimental mice and observe the changes of various indicators of rats of different ages, from 12 weeks to 84 weeks. The observations include left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), left ventricular short axis shortening rate (FS), LVEDP, LV+dp/dtmax, LV-dp/dtmax. At the same time, using the TUNEL labeling method, the left ventricular myocardial tissue was sliced, and the apoptosis index of subendocardial and subepicardial myocardial cells was calculated. Then 3 groups were randomly selected from the experimental group, and Western blotting was used to quantitatively detect apoptosis-related the expression of the proteins Bcl-2, Bax, and Fas were compared between the groups. After analysis and determination, it can be found that the apoptosis index of cardiomyocytes is positively correlated with LVMI, CVF, and PVCA (r is 0.83, 0.89, 0.72, respectively, p=0.00). Corresponding conclusions are drawn from the comparison of data. As hypertensive rats grow older, the apoptotic index of cardiomyocytes will continue to increase, and when the myocardial hypertrophy is severe to heart failure, the apoptotic index of cardiomyocytes will increase significantly. This shows that the increase in cardiomyocyte apoptosis is closely related to left heart remodeling, the development of myocardial fibrosis and overall cardiac dysfunction.

Speckle-tracking echocardiography in early diagnosis of lipotoxic myocardial damage in epicardial obesity

Epicardial obesity (EO) can lead to lipotoxic myocardial damage with the development of myocardial fibrosis, which underlie the impairment of left ventricular (LV) diastolic function. The identification of markers of lipotoxic myocardial damage is important at an early preclinical stage for preventive measures. Objective. To study the relationship of plasma levels of markers of insulin resistance and lipotoxic fibrosis with the parameters of LV mechanics in patients with EO. We hypothesized that there are significant differences in plasma levels of markers of insulin resistance and myocardial fibrosis and that they are associated with the parameters of LV mechanics in EO. Design and methods. The study included 143 men. Inclusion criteria: general obesity I–III degree. Exclusion criteria: type 2 diabetes mellitus, hypertension, LV diastolic dysfunction based on echocardiography (Echo). Patients were divided into 2 groups: EO (+) with epicardial fat thickness (tEAT) ≥ 7 mm (n = 70); EO (–) with tEAT &lt; 7 mm (n = 31). All patients were assessed for glucose, blood insulin, profibrotic factors and free fatty acids (FFA) using enzyme-linked immunosorbent assay. HOMA-IR insulin sensitivity index was calculated as (insulin × glucose)/22,5. With the help of speckle-tracking Echo, the mechanics of LV were studied (LV twisting, LV twisting ratio, time to LV twisting peak, LV untwisting ratio, time to LV untwisting peak). Results. The patients with EO (+) showed a statistically significant increase in the level of FFA up to 0,82 (0,39; 1,30) mmol/L (&lt; 0,0001) and HOMA-IR index up to 3,89 (2,02; 5,76) (&lt; 0,0001) in comparison with the group EO (–). There was a statistically significant effect of tEAT on the level of FFA (F = 7,90; p = 0,006) and on the development of insulin resistance (F = 14,85; p &lt; 0,001). The correlation analysis in the EO (+) group showed the relationship between FFA and type III collagen (r = 0,29, p = 0,01) and procollagen type I carboxy-terminal propeptide (PICP) (r = 0,26, p = 0,03), as well as between HOMA-IR and MMP-3 (r = 0,30, p = 0,01). In the EO (–) group, the relationship of profibrotic factors with the level of FFA and HOMA-IR was not found. There was also a significant relationship between LV untwisting ratio and level of FFA (r = 0,24, p = 0,04) in the group EO (+). Conclusions. Thus, an increase in the level of FFA in patients with EO may be accompanied by an increase in the level of some profibrotic factors and a LV untwisting violation determined by speckle-tracking Echo. Our data supports the need for assessing the FFA level and speckle-tracking Echo for the early diagnosis of LV diastolic dysfunction in patients with EO.

The Mystery of Diabetic Cardiomyopathy: From Early Concepts and Underlying Mechanisms to Novel Therapeutic Possibilities.

Diabetic patients are predisposed to diabetic cardiomyopathy, a specific form of cardiomyopathy which is characterized by the development of myocardial fibrosis, cardiomyocyte hypertrophy, and apoptosis that develops independently of concomitant macrovascular and microvascular diabetic complications. Its pathophysiology is multifactorial and poorly understood and no specific therapeutic guideline has yet been established. Diabetic cardiomyopathy is a challenging diagnosis, made after excluding other potential entities, treated with different pharmacotherapeutic agents targeting various pathophysiological pathways that need yet to be unraveled. It has great clinical importance as diabetes is a disease with pandemic proportions. This review focuses on the potential mechanisms contributing to this entity, diagnostic options, as well as on potential therapeutic interventions taking in consideration their clinical feasibility and limitations in everyday practice. Besides conventional therapies, we discuss novel therapeutic possibilities that have not yet been translated into clinical practice.

Pharmacogenetics as a Way for Personalizing Diuretic Therapy: Focus on Torasemide

Optimizing diuretic therapy in patients with chronic heart failure is a complicated problem with many unresolved questions. Diuretics take an important place in the treatment of heart failure, which are used in almost 80% of cases. Currently, there are not enough clinical studies, which comparative effectiveness of loop diuretics, as well as studies aimed at personalizing diuretic therapy. Torasemide has several advantages over other loop diuretics; high bioavailability, longer half-life and duration of action provide predictable diuresis. The presence of favorable neurohormonal effects, consisting in a decrease of sympathetic activity and inhibition of the renin-angiotensin-aldosterone system, leads to the fact that hypokalemia rarely occurs. In addition, torasemide slows development of myocardial fibrosis and fosters reverse ventricular remodelling. The use of personalization methods is one of the ways to increase the efficiency and safety of pharmacotherapy with diuretics. The polymorphism of genes encoding systems of biotransformation and transporters of drug is an important factor that determines the individual characteristics of a patient. Pharmacogenetics of torasemide may be of significant importance for pharmacokinetics and pharmacodynamics, influencing the intensity of the diuretic effect and side effects. The clearance of torasemide after oral administration may vary by 47% due to genetic characteristics: the participation of the OATP1B1 polymorphism is approximately 15.5%, the CYP2C9 polymorphism is 20%, and the OAT1 and OAT4 polymorphisms are 10%. Due to the significant differences in the pharmacokinetics of torasemide, further study of the pharmacodynamic characteristics of torasemide in patients with genetic polymorphism is necessary.

Characterization of cardiovascular injury in mice following partial-heart irradiation with clinically relevant dose and fractionation

Background and purposeLate cardiac toxicity is a major side effect of radiation therapy (RT) for breast cancer. We developed and characterized a mouse model of radiation-induced heart disease that mimics the dose, fractionation, and beam arrangement of left breast and chest wall RT. Material and methodsFemale wild-type (C57BL6/J) and atherosclerosis-prone apolipoprotein E-deficient (ApoE−/−) mice (on a C57BL/6J background) on regular chow were treated with 2 Gy × 25 fractions of partial-heart irradiation via opposed tangential beams to the left chest wall. The changes in myocardial perfusion and cardiac function of C57BL/6J mice were examined by single-photon emission computed tomography (SPECT) and echocardiography, respectively. In addition to SPECT and echocardiography, the formation of calcified plaques and changes in cardiac function of ApoE−/− mice were examined by dual-energy microCT (DE-CT) and pressure–volume (PV) loop analysis, respectively. The development of myocardial fibrosis was examined by histopathology. ResultsCompared to unirradiated controls, irradiated C57BL/6J mice showed no significant changes by SPECT or echocardiography up to 18 months after 2 Gy × 25 partial-heart irradiation even though irradiated mice exhibited a modest increase in myocardial fibrosis. For ApoE−/− mice, 2 Gy × 25 partial-heart irradiation did not cause significant changes by SPECT, DE-CT, or echocardiography. However, PV loop analysis revealed a significant decrease in load-dependent systolic and diastolic function measures including cardiac output, dV/dtmax and dV/dt min 12 months after RT. ConclusionsFollowing clinically relevant doses of partial-heart irradiation in C57BL/6J and ApoE−/− mice, assessment with noninvasive imaging modalities such as echocardiography, SPECT, and DE-CT yielded no evidence of decreased myocardial perfusion and cardiac dysfunction related to RT. However, invasive hemodynamic assessment with PV loop analysis indicated subtle, but significant, changes in cardiac function of irradiated ApoE−/− mice. PV loop analysis may be useful for future preclinical studies of radiation-induced heart disease, especially if subtle changes in cardiac function are expected.

Immune Dysregulation in Myocardial Fibrosis, Steatosis, and Heart Failure: Current Insights from HIV and the General Population.

HIV is an independent risk factor for heart failure (HF). Cardiac imaging studies in people with HIV (PWH) have identified myocardial pathologies, namely fibrosis and steatosis, that likely contribute to the higher risk of HF. In this review, we survey existing epidemiological, clinical, and mechanistic literature to identify potential pathways that may contribute to the burden of myocardial fibrosis and steatosis among PWH. Multiple cohort studies over the past 20years have demonstrated a roughly 2-fold higher risk of incident HF in PWH, as well as a disproportionate burden of myocardial fibrosis and steatosis in PWH without HF. Both myocardial fibrosis and steatosis are known contributors to HF in adults without HIV. Pathways involving the NLRP3 inflammasome, TGF-β1, and adipocyte dysfunction are known to play a crucial role in the development of myocardial fibrosis and steatosis. Upregulation of these pathways in HIV due to direct effects of viral proteins, persistent immune dysregulation, gut epithelial breakdown and dysbiosis, and toxicities from antiretroviral therapy may contribute to myocardial dysfunction in HIV. Understanding these pathways may lead to more precise diagnostic and therapeutic targets to curb HF in PWH. During the past three decades, observational and mechanistic studies have provided important insights into risk factors and pathways that may contribute to the increased HF risk in PWH. Future work is needed to characterize these pathways more precisely in mechanistic studies of PWH, with the goal of ultimately deriving valuable targets for prevention, early diagnosis, and treatment of HF in PWH.

Asymptomatic type 2 diabetes mellitus display a reduced myocardial deformation but adequate response during exercise.

The development of myocardial fibrosis is a major complication of Type 2 diabetes mellitus (T2DM), impairing myocardial deformation and, therefore, cardiac performance. It remains to be established whether abnormalities in longitudinal strain (LS) exaggerate or only occur in well-controlled T2DM, when exposed to exercise and, therefore, cardiac stress. We therefore studied left ventricular LS at rest and during exercise in T2DM patients vs. healthy controls. Exercise echocardiography was applied with combined breath-by-breath gas exchange analyses in asymptomatic, well-controlled (HbA1c: 6.9 ± 0.7%) T2DM patients (n = 36) and healthy controls (HC, n = 23). Left ventricular LS was assessed at rest and at peak exercise. Peak oxygen uptake (V̇O2peak) and workload (Wpeak) were similar between groups (p > 0.05). Diastolic (E, e's, E/e') and systolic function (left ventricular ejection fraction) were similar at rest and during exercise between groups (p > 0.05). LS (absolute values) was significantly lower at rest and during exercise in T2DM vs. HC (17.0 ± 2.9% vs. 19.8 ± 2% and 20.8 ± 4.0% vs. 23.3 ± 3.3%, respectively, p < 0.05). The response in myocardial deformation (the change in LS from rest up to peak exercise) was similar between groups (+ 3.8 ± 0.6% vs. + 3.6 ± 0.6%, in T2DM vs. HC, respectively, p > 0.05). Multiple regression revealed that HDL-cholesterol, fasted insulin levels and exercise tolerance accounted for 30.5% of the variance in response of myocardial deformation in the T2DM group (p = 0.002). Myocardial deformation is reduced in well-controlled T2DM and despite adequate responses, such differences persist during exercise. NCT03299790, initially released 09/12/2017.

CircUbe3a from M2 macrophage-derived small extracellular vesicles mediates myocardial fibrosis after acute myocardial infarction

Objective: This study aimed to explore the role of circular RNAs (circRNAs) in M2 macrophage (M2M)-derived small extracellular vesicles (SEVs) in myocardial fibrosis development.Methods: The regulatory role of M2M-derived extracellular vesicles (EVs) was evaluated in a mouse model of acute myocardial infarction. Immunofluorescence, quantitative real-time PCR (RT-qPCR), nanoparticle tracking analysis, Western blot analysis and electron microscopy were used to identify macrophages, large extracellular vesicles (LEVs) and SEVs. The circRNA expression profiles of M0 macrophages (M0Ms) and M2Ms were determined by microarray analysis. Bioinformatic analysis, cell coculture and cell proliferation assays were performed to investigate the expression, function, and regulatory mechanisms of circUbe3a in vitro. qPCR, RNA immunoprecipitation (RIP), dual-luciferase reporter assays, RNA fluorescence in situ hybridization (RNA-FISH), Western blot analysis and a series of rescue experiments were used to verify the correlation among circUbe3a, miR-138-5p and RhoC.Results: CircUbe3a from M2M-derived SEVs triggered functional changes in cardiac fibroblasts (CFs). CircUbe3a was synthesized and loaded into SEVs during increased M2M infiltration after myocardial infarction. The fusion of the released SEVs with the plasma membrane likely caused the release of circUbe3a into the cytosol of CFs. Silencing or overexpressing circUbe3a altered CF proliferation, migration, and phenotypic transformation in vitro. We confirmed that circUbe3a plays a crucial role in enhancing functional changes in CFs by sponging miR-138-5p and then translationally repressing RhoC in vitro. In vivo, the addition of M2M-derived SEVs or overexpression of circUbe3a significantly exacerbated myocardial fibrosis after acute myocardial infarction, and these effects were partially abolished by circUbe3a-specific shRNA.Conclusions: Our findings suggest that M2M-derived circUbe3a-containing SEVs promote the proliferation, migration, and phenotypic transformation of CFs by directly targeting the miR-138-5p/RhoC axis, which may also exacerbate myocardial fibrosis after acute myocardial infarction.