Heart Remodeling Research Articles

AP-1 signaling modulates cardiac fibroblast stress responses.

Matrix remodeling outcomes largely dictate patient survival post myocardial infarction. Moreover, human-restricted noncoding regulatory elements have been shown to worsen fibrosis, but their mechanism of action remains elusive. Here, we demonstrate, using induced pluripotent stem cell-derived cardiac fibroblasts (iCFs), that inflammatory ligands abundant in the remodeling heart after infarction activate AP-1 transcription factor signaling pathways resulting in fibrotic responses. This observed signaling induces deposition of fibronectin matrix and is further capable of supporting immune cell adhesion; pathway inhibition blocks iCF matrix production and cell adhesion. Polymorphisms in the noncoding regulatory elements within the 9p21 locus (also referred to as ANRIL) redirect stress programs, and in iCFs, they transcriptionally silence the AP-1 inducible transcription factor GATA5. The presence of these polymorphisms modulate iCF matrix production and assembly and reduce cell-cell signaling. These data suggest that this signaling axis is a critical modulator of cardiac disease models and might be influenced by noncoding regulatory elements.

17R-Resolvin D1 Improves Inflammatory Cardiomyopathy in a Mouse Model of Sickle Cell Disease

Sickle cell disease (SCD) is a severely invalidating genetic red cell disorder. Inflammatory vasculopathy and cardiopulmonary complications markedly impact quality of life and survival. Limited studies are available on the pathogenesis of sickle cell related cardiomyopathy. However, the combination of inflammatory vasculopathy, heart ischemia, and myocardial fibrosis have been suggested to play a role in sickle cell related cardiomyopathy. This is supported by the amelioration of cardiomyopathy in SCD patients, early and intensively treated with either hydroxyurea or chronic transfusion regimen (Niss O et al. Blood 140: 1322, 2022). Recently, we have highlighted an impairment of pro-resolving events in SCD with a deleterious effect on acute sickle cell related organ damage (Matte A et al. Blood 133: 252, 2019). Growing evidence links impairment of pro-resolving mechanisms with atherosclerosis and ischemic cardiomyopathy (Kain V et al. J Mol Cell Cardiol 84: 24, 2015; Conte MS et al. JCI 128: 3727, 2018). Among specialized pro-resolving mediators, 17R-resolvin D1 (17R-RvD1) has been shown to play important protective actions in cardiovascular diseases (Kain V et al. J Mol Cell Cardiol 84: 24, 2015). Here, we first determined the appropriate window of time to study cardiac response to hypoxia/reoxygenation (H/R) stress, mimicking sickle cell related acute vaso-occlusive crisis. We show that humanized SCD mice (TT model) exposed to H/R (10 hours hypoxia 8% oxygen, followed by 3 hours reoxygenation) display increased markers of myocardial dysfunction with neutrophil heart infiltration compared to either SCD mice under normoxia or to healthy (AA) animals exposed to H/R stress. With integrated proteomic and miRNA analyses we have identified upregulation of proteins and miRNAs involved in fibrosis, hypertrophy of the heart, and cardiomyocyte apoptosis. Differentially expressed miRNAs in SCD-hearts compared to AA included miR-16-5p, miR-122-5p, and miR-206-3p, which are involved in angiogenesis and heart fibrosis and hypertrophy. Upregulated proteins in SCD hearts in response to H/R encompassed: NF-kB, Nrf2, hemeoxygenase-1, glutathione peroxidase, and peroxiredoxins (associated to response to oxidative stress), the profibrotic factors FGF and PDGF as well as the TGF-ß1 receptor, and the pro-angiogenic VEGF pathway. Treatment with 17R-RvD1 (100 ng administrated by gavage 1 hour before H/R, see also Matte A et al. Blood 133: 252, 2019) protected heart of SCD mice from H/R-induced stress as supported by significant reduction of ANP, a marker of cardiovascular dysfunction, decrease in neutrophil infiltration, and NF-kB activation (Figure 1). 17R-RvD1 also diminished the H/R-driven upregulation of miR-16-5p, while it enhanced miR-206-3p that was downregulated by H/R, suggesting that 17R-RvD1 can reduce cardiac fibrosis and other pathological processes associated with these miRNAs in SCD. We also found that 17R-RvD1 administration to SCD mice blunted the activation of TGF-ß1 pathway and of markers of extracellular remodeling, supporting the beneficial effect of 17R-RvD1 against H/R stress. Taken together, our data show that 17R-RvD1 reduced heart remodeling and fibrosis in SCD mice undergoing H/R, a model of acute VOCs. This improved understanding in basic pathophysiology of SCD-related inflammatory cardiomyopathy, providing new evidence for protective therapeutic effects of 17R-RvD1 on SCD cardiovascular diseases.

Rhythm and Conductivity Disorders in Patients with Hypertension

Purpose of the study: to study the prevalence and structure of arrhythmias and conduction disorders and various types of heart remodeling in patients with hypertension among men and women. Material and methods: The study was conducted in the Bukhara branch of the Republican Specialized Scientific and Practical Medical Center for Cardiology involving 75 men and 43 women with HD; The mean age of men with hypertension and rhythm and conduction disorders was 62.86±1.91 years, and women - 68.29±2.34 years (p<0.05). An anamnesis, ambulatory blood pressure monitoring (ABPM), Holter monitoring of the electrocardiogram (HM-ECG) were taken. Results. Among patients with GB, rhythm and conduction disturbances were detected in 64% of men and 46.51% of women. Men with hypertension and rhythm and conduction disorders are younger than women (58.86±1.91 years and 68.29±2.34 years, respectively). Among rhythm disturbances, SVT (34.69% of men and 56.52% of women), PVC (28.57% of men and 26.09% of women) and AF (14.28% of men and 21.73% of women) were more common. The most common finding on ultrasound of the heart was dilatation of the left atrium (53.33% of men and 37.20% of women) and both atria (6.67% of men and 2.32% of women); LVH - in 56% of men and 44.18% of women; pulmonary hypertension - in 18.67% of men and 25.58% of women. It is necessary to dynamically monitor patients with hypertension with regular examinations to identify signs of disorders in the state of the cardiovascular system, in particular rhythm and conduction disturbances.

A Retrospective Cohort Evaluation of Left Ventricular Remodeling, Perioperative Complications and Outcome in Medium and Large Size Dogs with Patent Ductus Arteriosus after Percutaneous Closure.

This retrospective cohort study included one hundred fifty-seven medium and large-size dogs with the aim of evaluating the effect of signalment and echocardiographic features on complications, outcomes and left ventricular modifications before and after patent ductus arteriosus (PDA) closure. The patients were divided in two groups based on the heart remodeling after closure: Group A included dogs that had a reduction in the end-systolic volume index (ESVI) after closure compared to the ESVI measured before; Group B included dogs without a reduction in ESVI after closure. Body weight, minimal ductal diameter (MDD) of PDA, end-diastolic volume index and presence of arrhythmias at presentation were significantly higher in Group B compared to Group A. The shortening fraction and ejection fraction after closure were reduced in both groups, but in Group B there was a major reduction, and the mean values indicated a possible systolic dysfunction. Complications during the procedure and death due to cardiac reasons were greater in Group B compared to Group A. In conclusion, a higher body weight, a larger MDD, a more severe heart enlargement or arrhythmias at presentation increased the risk of developing a worsening structural and functional condition after ductal closure, and this can be associated with perioperative complications and cardiac death.

Chronic Heart Failure and Progressive Angina

Chronic heart failure (CHF) is a “pathophysiological syndrome in which, as a result of a particular disease of the cardiovascular system or under the influence of other etiological causes, the heart’s ability to fill or empty is impaired, accompanied by an imbalance of the neurohumoral systems (RAAS, sympathoadrenal system, natriuretic peptides, kallikrein-kinin system). As well as the development of vasoconstriction and fluid retention, there is a dysfunction of the heart (remodeling) and other target organs (proliferation), as well as a discrepancy between the provision of organs and tissues of the body with blood and oxygen with their metabolic needs” [1-3].

Left heart remodelling in hypertensive patients: a comprehensive echocardiography and computed tomography study

ObjectivesThis study aimed to assess left heart remodelling changes in hypertension, excluding underlying ischaemic heart disease, utilising computed tomography coronary angiography (CTCA) and transthoracic echocardiography (TTE).MethodsA total of 178 patients (mean age 60 ± 9 years, 53% female) were enrolled in the study: Group 1 consisted of patients with essential hypertension (n = 96, Group 1), and Group 2 served as age-matched controls (n = 82, Group 2). All participants underwent both CTCA and TTE. TTE measurements included left ventricle (LV) concentricity and function and left atrial (LA) volume and function. Using both CTCA and TTE, we measured LV diastasis volume (LVdias) and LA diastasis volume (LAdias).ResultsLV mass index and LV mass/height2.7 were similar in both the groups. However, Group 1 had a higher prevalence of concentric LV remodelling, characterised by a larger mean LV wall thickness, increased relative wall thickness ratio, and a reduced ratio of LV end-diastolic volume (LVED) index to mean wall thickness (55 ± 14 vs. 65 ± 15, p = 0.0007). Group 1 showed higher LAdias and LA minimal volumes, while LA reservoir function was lower in Group 2. The LVdias/LAdias ratio was lower in Group 1 compared to Group 2 (TTE 1.77 ± 0.61 vs. 2.24 ± 1.24, p = 0.0025, CTCA 1.50 ± 0.23 vs. 1.69 ± 0.41, p = 0.0002). A composite score based on four combined TTE parameters, namely, LVED index/mean wall thickness ≤57, ratio of early diastolic mitral inflow to mitral annular tissue velocities (E/e’) >8, LVdias/LAdias ≤1.62, and LA reservoir function ≤0.58, yielded the highest discriminatory power (area under the curve—AUC = 0.772) for distinguishing patients with hypertensive heart disease (HHD). Collectively, we refer to these parameters as the LEDA score, with each parameter scored as one point. For LEDA scores of 0, 1, 2, 3, 4, the probability of underlying HHD was 0%, 23%, 59%, 80%, and 95%, respectively. Furthermore, a CTCA-derived LVdias/LAdias ≤1.76, considered as a single parameter, demonstrated modest accuracy in differentiating patients with HHD (AUC = 0.646).ConclusionsThe TTE LEDA score, based on four parameters, namely, LVED index/mean wall thickness, E/e’, LVdias/LAdias, and LA reservoir function, proved to be the most effective in defining left heart remodelling in hypertension.

Results of long-term riociguat therapy, including a switching strategy from sildenafil, in patients with pulmonary hypertension of various genesis

Aim: to study the influence of riociguat on the functional and hemodynamic status, remodeling of the right heart, as well as the safety of therapy in both previously untreated patients with idiopathic pulmonary arterial hypertension (IPAH) and inoperable chronic thromboembolic PH (CTEPH), and those not achieved treatment goals with sildenafil therapy and switching to riociguat.Materials and methods. A total of 161 pts with precapillary PH were included in the study; 137 pts completed the three-year observation period. Of 55 IPAH pts riociguat was started after diagnosis verification in 39 pts (subgroup 1); 16 pts previously taking sildenafil who did not achieve treatment goals comprised subgroup 2 of switching to riociguat. Of 82 inoperable CTEPH pts riociguat was started in 45 naїve pts; a switching strategy riociguat was implemented in 37 pts after 24-hour withdrawal of sildenafil. The dose titration of riociguat was started from 1 mg TID according to the standard algorithm up to 7.5 mg/day. By month 36 92.4% and 94.8% of pts with IPAH and CTEPH, respectively, received 7.5 mg/day. At baseline, at month 12, 24 and 36 all pts underwent a 6-minute walking test (6MWT) with the assessment of the dyspnea index according to the Borg scale and SpO2, echocardiography (Echo), right heart catheterization (RHC), and the safety profile was assessed.Results. At baseline, the proportion of pts with FC III-IV in CTEPH group compared to IPAH group, was significantly higher (70.7% vs 41.8%)); the distance in T6MX (d6MWT) was 291 [232;385] m vs 379 [300;448] m (p<0.001). CTEPH pts had lower values of sPAP, PVR, SaO2 and SvO2 assessed by RHC. In the switching subgroups 2 of pts with IPAH and CTEPH, achieved levels of sPAP (p=0.01), sRAP (p=0.001) and PVR (p=0.01) (RHC) were significantly lower than in subgroups 1. The baseline levels of CI and SV were significantly higher in subgroups 2 (p<0.05). During riociguat treatment in both subgroups of IPAH, a significant increase in d6MWT was achieved by 6 months with FC I-II (WHO) in 75% and 70% of patients. In the subgroup 1 to 36 months the greatest increase by 97m was achieved; in the switching subgroup the increase in d6MWT was noticed by month 6, which was maintained by month 36. In CTEPH patients, there was a significant improvement in FC (p=0.001) with ∆dT6MX 48m (p=0.001). In subgroup 1 with CTEPH, the d6MWT increase was 68.2m (p = 0.001), reaching 82.6m by month 36. In subgroup 2 the significant change of d6MWT were noted by the 1st year of FU, reaching 136.6m by month 36. In IPAH and CTEPH pts by month 36 of riociguat therapy, a significant decrease of mPAP, SPAP were found by echo, which was confirmed by RHC; there was a decrease in the basal size of the right ventricle (RV) (p=0.04) and an increase in RV FAC (p=0.04 and p=0.03, respectively). In subgroups 1, ∆SvO2 in ts with IPAH and CTEPH were significantly higher compared to subgroups 2. During FU period the proportion of low-risk pts increased to 26.7% in IPAH group and 44.8% in CTEPH group at month 36. In subgroups 2 riociguat therapy resulted in maintenance of treatment regimens throughout the year. Only 6.2% of pts by month 24 and 36 required the prescription of a 3d specific drug. No serious adverse events (AEs) were observed during treatment. The most common AEs were nasopharyngitis, nasal congestion, and dyspnea.Conclusions: Riociguat therapy for 36 months demonstrated a persistent positive effect on the functional and hemodynamic status, remodeling of the right heart both in previously untreated patients with IPH and inoperable CTEPH, and in patients from the switching groups who did not achieve treatment goals with sildenafil therapy.

An exploratory human study investigating the influence of type 2 diabetes on macrophage phenotype after myocardial infarction

BackgroundMyocardial infarction (MI) is the primary cause of death in subjects with type 2 diabetes (T2D) and their in-hospital mortality after MI is still elevated compared with those without T2D. Therefore, it is of crucial importance to identify possible mechanisms of worse clinical outcomes and mortality in T2D subjects. Monocyte/macrophage-mediated immune response plays an important role in heart remodelling to limit functional deterioration after MI. Indeed, first pro-inflammatory macrophages digest damaged tissue, then anti-inflammatory macrophages become prevalent and promote tissue repair. Here, we hypothesize that the worse clinical outcomes in patients with T2D could be the consequence of a defective or a delayed polarization of macrophages toward an anti-inflammatory phenotype. Methods and resultsIn an exploratory human study, circulating monocytes from male patients with or without T2D at different time-points after MI were in vitro differentiated toward pro- or anti-inflammatory macrophages. The results of this pilot study suggest that the phenotype of circulating monocytes, as well as the pro- and anti-inflammatory macrophage polarization, or the kinetics of the pro- and anti-inflammatory polarization, is not influenced by T2D. ConclusionFurther studies will be necessary to understand the real contribution of macrophages after MI in humans.

Long-term structural right heart remodeling following transcatheter annuloplasty for treating severe tricuspid regurgitation assessed by CT scan

Abstract Background Transcatheter tricuspid annuloplasty has emerged as an attractive percutaneous therapy for patients with severe symptomatic tricuspid regurgitation. Cardioband (Edwards) was the first dedicated CE marked percutaneous device for tricuspid regurgitation. Despite mid-long-term clinical safety and efficacy demonstrated in early feasibility trials and registries, there is no data about its impact on right heart structural remodeling using computed tomography (CT). Our aim was to assess right heart remodeling and changes in the tricuspid annulus (TA) one year after Cardioband implantation. Methods A total of 30 patients were prospectively included in the study; 21 of them had baseline and at least 1-year follow-up CT analysis. The average time from the basal CT scan and the procedure was 118±136 days, and from the intervention to follow-up CT scan was 468±251 days. 2D and 3D analyses were performed with 3mensio version 10.3 at baseline and at least 12 months after Cardioband implantation. Results There was a significant decrease in right ventricular dimensions at follow-up (right ventricular basal diameter was 53.65 ± 8.45 mm at baseline Vs 48.54 ± 9.12 mm at 1-year follow-up; right ventricular mid cavity diameter was 40.30 ± 9.10 mm at baseline Vs 34.22 ± 9.22 at the end of follow-up, and right ventricular longitudinal diameter was 75.43 ± 9.85 mm at baseline Vs 69.95 ± 9.96 mm at the end of follow-up, all of them were statistically significant). A reduction in right atrial dimension was also observed (longitudinal diameter 66.86 ± 7.63 mm at baseline Vs 64.89 ± 9.99 mm at the end of follow-up; transverse diameter of 61.62 ± 8.38 mm at baseline Vs 60.59 ± 8.3 mm at the end of follow-up, p<0.001). There was a significant decrease in the area and diameters of the dilated TA (area at baseline 16.51 ± 3.06 cm2 vs 8.90 ± 2.71 cm2 at the end of follow-up, p=0.02; septolateral diameter 45.42 ± 5.02 mm at baseline vs 33.87 ± 5.09 mm at the end of follow-up, p=0.01). Conclusions Long-term favorable right ventricular chambers and TA remodeling was observed following Cardioband implantation assessed by CT scan. This finding could explain the long-term clinical benefit demonstrated in feasibility studies.Right heart remodeling after Cardioband

Association of atrial fibrillation symptom with clinical outcomes: a prospective multicenter registry study

Abstract Background and Objectives Atrial fibrillation (AF) is usually classified on the basis of the disease subtype. However, this characterization does not capture the full heterogeneity of AF. This study was performed to evaluate whether the remodeling of heart, treatment of AF, and clinical outcome is different according to the symptom of AF. Patients and Methods In the prospective, multicenter study of AF registry, we identified 10,210 patients with non-valvular AF (mean age, 66.7 years; 35.3% were women) enrolled between June 2016 and March 2022 with eligible follow-up visits. The patients were classified into two groups according to the presence of AF symptoms. Clinical factors related with AF symptoms were analyzed. The primary outcome was defined as a composite of all cause death, ischemic stroke, transient ischemic attack, systemic embolism, myocardial infarction, and hospitalization for heart failure. Results Among 10,210 patients, 4,327 (42%) were symptomatic AF, and 5,883 (58%) were asymptomatic AF. The asymptomatic group had older age, more male sex, comorbidities such as hypertension and diabetes mellitus, larger LA AP diameter (43.6 vs. 42.2, P <0.001), and higher E/E’(10.4 vs. 10.0, P <0.001). During median follow-up of 32.9 (29.5 ∼ 36.4) months, incidence of the primary outcome in Asymptomatic vs. Symptomatic were 1.44 and 1.45 per 100 person-year, respectively. In multivariable Cox regression analysis, AF symptoms were not associated with an increased risk of the primary outcome (HR 1.02; 95% CI, 0.81 ∼ 1.29, P = 0.871). In linear regression, symptom of AF was negatively associated with LA AP diameter (β coefficient -0.43, 95% CI -0.76 ∼ -0.11, P = 0.009). Conclusions In the multicenter prospective AF registry, the presence of AF symptoms was not related to cardiovascular outcomes. However, AF symptoms were related to LA remodeling.Cumulative incidence for primary outcomeLinear regression for LA AP diameter

Biomineralized ceria nanoparticles target the heart to improve diabetic cardiac remodeling by regulating mitochondrial oxidative stress and decreasing excessive mitophagy

Abstract Background An altered state of cardiomyocytes due to high glucose concentrations results in cell hypertrophy, leading to diabetic cardiomyopathy (DCM).The molecular regulatory process of mitochondrial dyshomeostasis and mitophagy, oxidative stress, and reactive oxygen species (ROS) production in diabetes is still not fully understood. Mitochondrial dyshomeostasis and mitophagy could be critical factors in the heart remodeling that occurs in diabetes. Purpose Our transcriptome sequencing of heart tissue revealed upregulation of the gene encoding the transferrin receptor (TfR) in the diabetic rat (Figure 1A). We then validated in vitro that high glucose increased TfR protein expression in the HL-1 cell line (Figure 1B). Herein, we developed a novel therapeutic ceria nanoparticle via biomineralization using transferrin (Tf) protein as a temple and assessed its targeted therapy for DM-induced cardiac remodeling via Tf-TfR mediated endocytosis. Method We synthesized Tf protein-based ceria NPs (CeO2@Tf) via biomineralization. Then the physicochemical and biological properties of NPs were characterized. Cellular uptake, cytotoxicity test, intracellularmitochondrial membrane potential (MMP), and ROS were verified with mouse cardiomyocytes HL-1 cells line. Afterward, the male C57BL/6N mice were randomly divided into control, DM, DM+Metformin (Met), and DM+NPs groups with eight weeks of treatment. Heart structure and function were measured by echocardiographic. The heart tissues were stained with hematoxylin, eosin (H&E), and Masson's trichrome stain to observe morphological changes and fibrosis. Western blot was used to determine mitochondrial homeostasis regulation-related proteins and mitophagy pathway. Results TEM and X-ray photoelectron spectroscopy characterized the properties successfully. MTT assay shows that HL-1 cell viabilities were not influenced by CeO2@Tf at 200 µM.High-glucose treatment led to increased ROS and decreased intracellular MMP in HL-1 cells. DM mice cardiac transcriptome sequencing results showed upregulation of transferrin receptor gene expression. Echocardiographic showed increased LAD and abnormal diastolic and systolic functions. All these abnormal changes were improved in the DM+ Met and DM+NPs groups. Our investigations revealed proteins linked to the PINK1-Parkin signaling pathway (Figure 2A-B) and found that the level of mitophagy in the diabetic group was overly high, which was improved after the application of CeO2@Tf. We observed the mitochondrial autophagosomes through transmission electron microscopy (Figure 2C). The autophagosomes in the diabetic group increased significantly and improved after treatment with CeO2@Tf. Conclusions These consistent biochemical and histopathological results suggest that the biomimetic mineralization of CeO2@Tf could inhibit oxidative stress and improve mitochondrial function in vitro induced by high-glucose and in vivo caused by DM, alleviating cardiac remodeling in DM mice.

Right heart remodeling and outcomes of patients with tricuspid regurgitation

Abstract Background Albeit long neglected, significant (at least moderate, ≥ 2+) tricuspid regurgitation (TR) is currently known to be associated with increased mortality, and has thus become a relevant therapeutic target [1-3]. Recent and somewhat preliminary evidence has shown, however, that different subtypes of TR might respond differently to current therapeutic options [4-5]. In fact, secondary TR, rather than being a single entity, can develop because of either right ventricular (RV) remodelling (i.e functional TR) or tricuspid annulus (TA) dilation secondary to right atrial (RA) dilation (i.e isolated TR). Purpose The aim of this meta-analysis was to study the association between right heart remodeling and long-term all-cause mortality in a population of patients with significant TR, independent of the treatment option. Methods MEDLINE, ISI Web of Science, and SCOPUS databases were searched for studies published up to July 2022. Studies reporting data on at least one echocardiographic RV anatomic and/or functional parameter and outcome in patients with significant TR were included. This study was designed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) requirements. The primary endpoint was long-term all-cause mortality. Results Out of 3152 studies, a total of 14 were included in the final analytic synthesis, enrolling 4394 subjects. The median follow-up was 33 [24–51] months. Overall, long-term all-cause mortality was 31% (95% confidence interval [CI]: 20-41%, p = <0.001; Figure 1); however, a significant difference was noted in the medical subgroup vs. the surgery subgroup (43% [32-53%] vs 11% [20-41%]). By means of a meta-regression analysis, a significant and inverse relation was found between tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (RV-FAC) and mortality (11 studies enrolling 3551 subjects, coefficient -0.063 [-0.111 to -0.014], p = 0.011; 9 studies, 2975 subjects, coefficient -0.044 [-0.059 to -0.029], p < 0.001, respectively; Figure 2A and 2B), whereas a significant and concordant relation was found between TA dimension, RA area and mortality (7 studies, 2986 subjects, coefficient 0.003 [0.002 to 0.005], p < 0.001; 6 studies, 1920 subjects, coefficient -0.019 [-0.025 to -0.013], p < 0.001, respectively; Figure 2C and 2D). Conclusions The higher mortality associated with right ventricular dysfunction and reduced mortality with increasing right atrial dilatation suggest a better prognostic outcome for isolated TR than functional TR. Careful assessment of right heart anatomy and function is warranted, as it might foster the identification of different subtypes of TR with unique prognoses.Forest plot all-cause mortalityResult of the meta-regression analysis

Roles of aldosterone on ventricular arrhythmias, and associated gap junction and ion channel remodeling in hypertrophic heart

Abstract Background Ventricular arrhythmias are critical causes of death in patients with chronic heart failure (CHF). Aldosterone (Ald) is an exacerbating factor of CHF and mineral corticoid receptor antagonist (MRA) is usual drug for the management of CHF. MRA also suppressed sudden cardiac death, however, mechanisms of these effects remain unknown. We investigated the effects of MRA on ventricular arrhythmias and arrhythmogenic factors using Dahl Salt sensitive (DS) rats. Methods (in vivo) DS rats were divided into three groups; low salt group (LS), high salt group (HS), and eplerenone-, an MRA, treated high salt group (HS+EPL). Low salt (0.3% NaCl) or high salt (8% NaCl) were administrated for 8 weeks and EPL was administrated in the last 4 weeks. Cardiac geometry and function were assessed by echocardiography. Susceptibility of ventricular arrhythmias were assessed using programmed stimulation. Myocyte hypertrophy and cardiac fibrosis were examined by Masson’s trichrome staining. Expression and distribution of connexin43 (Cx43) were examined by immunostaining and western blotting. mRNA expression of Ca transient-related factors, such as phospholamban, SERCA2a, and ryanosin 2, and potassium ion channel-related factors, such as KCNE1 and KCNQ1, was examined by RT-PCR. (in vitro) Ald (1-100 nM) was administrated to cultured rat neonatal cardiomyocytes. Expression of Cx43, Ca transient-related, and potassium ion channel-related factors are also examined as mentioned above. Effects of Src tyrosin kinase inhibitor, PP2, and ERK inhibitor, PD98059, on Ald-induced Cx43 reduction were examined by RT-PCR and immunostaining. Results Systolic blood pressure and Ald concentrations in cardiac tissue were higher in HS group than LS group, and EPL did not affect them. In HS group left ventricular hypertrophy, dilatation and systolic dysfunction were observed in association with myocyte hypertrophy and interstitial fibrosis. EPL significantly recovered cardiac function and histological impairments. In addition, elongation of QTc in ECG and susceptibility of ventricular tachycardia were remarkable in HS group rather than LS and EPL attenuated them. Distribution of Cx43 was scattered in HS group, and EPL attenuated these changes. Decrease in SERCA2a and increase in KCNE1/KCNQ1 mRNA expression were found in HS group, and these changes were attenuated by EPL. In cultured myocytes, Ald decreased Cx43 mRNA and protein expression in a dose dependent fashion. Ald-induced Cx43 reduction was inhibited by PP2 and PD98059. In addition, Ald (100 nM) also decreased SERCA2a and increased KCNE1/KCNQ1 mRNA expression. Conclusion These results indicate that Ald reduced and dispersed the Cx43 expression reduction and dispersion through Src tyrosin kinase and ERK signaling pathways, and also mediated SRECA2A and KCNE1/KCNQ1 expression, which induced QTc prolongation and susceptibility of lethal ventricular arrhythmias in hypertensive cardiac hypertrophy.

Regulatory roles of the N6-methyladenosine demethylase FTO in cardiac remodeling

Abstract Background The most prevalent internal RNA modification, N6-methyladenosine (m6A), serves as an additional layer of transcriptional and translational regulation. Methyl transferases (like METTL3) and demethylases (e.g., FTO) are the enzymes that catalyze m6A methylations. Our result showed that loss of FTO causes maladaptive cardiac remodeling in rodent hearts, which is consistent with other studies that emphasized the importance of FTO-dependent m6A RNA methylation in maintaining cardiac homeostasis, ventricular hypertrophy, and heart failure. Despite the fact that FTO is essential for stress-induced cardiac hypertrophy, its underlying functional mechanisms in regulating maladaptive cardiac remodeling are not yet known. Purpose In this study, we showed the necessity of FTO dependent m6A methylation in coordinating the molecular and signaling events that are engaged in cardiac hypertrophy, and further identified the detrimental signaling mechanisms that are regulated by FTO during pathological remodeling. Methods Firstly, the control and FTO-cKO (cardiomyocyte specific FTO knockout) group mice were subjected to sham and TAC (transverse aortic constriction) operation. Echocardiography was performed 1 week post-TAC. Secondly, m6A RNA immunoprecipitation (meRIP) sequencing were performed from the isolated mice heart tissue. Additionally, the effect of apoptosis and mTORC1 upon FTO depletion were analysed in both rodents and iPS-CMs. In vitro the interrelation between FTO demethylase, mTORC1 and autophagy in the regulation of cardiac apoptosis were identified by 1. inhibiting mTORC1 pathway with specific inhibitors, and by 2. inhibiting 'late autophagy' in FTO silenced iPS-CMs. Results In contrast to control mice, which exhibit concentric hypertrophy at the beginning of induced pressure overload (PO), echo analysis of one week post-TAC revealed that FTOcKO mice develop a DCM-like phenotype. Further, MeRIP-seq data showed that there is deregulation in the m6A methylation with FTO depletion. Around 114 differently hypermethylated transcripts and 58 differentially hypomethylated transcripts were discovered in FTOcKO sham as compared to Control sham; these transcripts are involved in the control of apoptosis, the mTORC1 signaling pathway, lysosomal biogenesis, and autophagy. In both rodents and iPS-CMs, FTO ablation dramatically enhances cardiac apoptosis and the mTORC1 signaling pathway. Furthermore, inhibition of mTORC1 pathway attenuates cardiac apoptosis in siFTO-iPS-CMs. Moreover, autophagic flux analysis revealed that FTO depletion cause autophagic flux impairment and exacerbate cardiac apoptosis. However, the autophagic flux is ameliorated with mTORC1 inhibition in late-autophagy inhibited siFTO-iPS-CMs. Conclusion Our data unravel the novel roles of FTO demethylase in the course of cardiac remodeling, which opens doors to therapeutic interventions in the treatment of cardiac hypertrophy and heart failure.

EVs derived from physiologically loaded myocardial slices affect remodelling of overloaded myocardial slices

Abstract Introduction Mechanical load is an important determinant of cardiac output, and excessive mechanical load can lead to heart remodelling, and ultimately failure. Cardiac intercellular communication is partially mediated by extracellular vesicles (EVs), which are 30-200 nm sized nanoparticles acting as shuttles of many bioactive cargoes that modulate cell behaviour, such as microRNAs. Living myocardial slices are an ideal platform to study how mechanical load affect intercellular communication through EVs, as they can be manipulated to obtain different degrees of preload and are an organotypic multicellular platform that retains the electrophysiology and extracellular matrix of the adult myocardial tissue. Purpose The aim of the study is to investigate how EVs derived from physiologically-loaded slices modulate the myocardial remodelling of overloaded slices. Methods 300 µm slices were obtained from the left ventricle of 300-350 g male Sprague Dawley rats. Mechanical load was applied by stretching the slices to either 2.2 or 2.4 µm of their sarcomere length, to recapitulate physiological and overloaded condition, respectively. Following 48-hours of biomimetic culture, force-stretch relationship of the slices was assessed, the tissue collected for RNA and protein extraction and the media of physiological slices was harvested for EVs isolation by size exclusion chromatography. Physiological EVs were then applied onto overloaded slices (1x108 EVs/slice) and cultured for 48-hours to assess force-stretch relationship, and protein and mRNA expression associated with cardiac remodelling. Physiological and overloaded EVs content was analysed through a microRNA array. Results Physiological slices had a significantly higher contractility (P < 0.05), higher blood vessel density (P < 0.0001) and lower apoptosis (P<0.01) compared to overloaded slices. Application of physiological EVs on overloaded slices restored their contractility (P<0.05), attenuated apoptosis by reducing protein PARP-1 expression (P<0.05) and reduced blood vessels density loss (P< 0.01), as shown by Isolectin B4 staining and increased mRNA levels of VEGF. microRNAs analysis showed significant downregulation of miR-346 and miR-16-5p and upregulation of miR-143-3p miR-378a-3p in physiological EVs, compared to overloaded. The upregulation or downregulation of these microRNAs was positively associated with cardiac apoptosis and migration of vascular smooth muscle cells. Conclusions Physiological EVs affect remodelling in overloaded slices. This is likely due to an effect on apoptosis or to an indirect effect on endothelial cells. Further validation and mechanistic studies with miRNAs selected candidates may reveal interesting therapeutic targets for heart failure.

Assessment of systemic inflammation activity, myocardial structure and functional features, their relationship in patients with multiple myeloma, receiving bortezomib therapy

To study the dynamics of calculated indices [neutrophil-lymphocyte ratio (NLR); systemic inflammation index (SIV)] and biomarkers of systemic inflammation [interleukin-1β (IL-1β); high-sensitivity C-reactive protein (hsCRP)], parameters of the structure-and-function state of the myocardium and intracardiac hemodynamics, and their relationship in patients newly diagnosed with multiple myeloma (MM) at the onset of the disease and after 6 courses of chemotherapy (CT) containing the proteasome inhibitor bortezomib. This prospective study included 30 patients aged 63.8±10.0 years diagnosed with MM; 17 (56.7 %) of them were men. The following tests were performed for all patients: measurement of IL-1β and hsCRP, calculation of the inflammation indexes NLR and SIV, transthoracic echocardiography before and after 6 courses of bortezomib-containing CT. At the time of study completion, 9 patients dropped out due to reasons not related to cardiovascular complications of CT. The antitumor therapy was associated with increases of immune-inflammation indexes: NLR increased from 1.54 [1.02; 1.83] to 2.9 [1.9; 4.35] (p=0.009) and SIV increased from 402.95 [230.5; 534.0] to 1102.2 [453.1; 1307.9] (р=0.014). IL-1β increased from 5.15 [4.05; 5.77] to 6.22 [5.66; 6.52] pg/ml remaining within the reference range (p=0.142) whereas hsCRP decreased from 1.02 [0.02; 2.71] to 0.02 [0.02; 0.82] IU/l (p=0.138). Statistically significant changes in parameters of heart remodeling and clinical picture of cardiovascular complications were not observed. A correlation analysis showed significant inverse correlations of hsCRP with left ventricular ejection fraction (LV EF) (r= -0.557; p=0.003), the number of plasma cells (PC) with LV EF (r= -0.443; p=0.023), and a direct correlation of the number of PC with hsCRP (r=0.433; p=0.022). During the study, the accepted criteria for cardiotoxicity of bortezomib-containing chemotherapy in patients with MM, were not met. The identified correlations between the level of markers for acute inflammation, indexes of intracardiac hemodynamics, and the immediate MM substrate may indicate the role of chronic low-intensity inflammation in the pathogenesis of myocardial remodeling in patients with MM. This necessitates further studies on larger samples of patients to assess the prognostic significance.

Assessment of systemic inflammation activity, myocardial structure and functional features, their relationship in patients with multiple myeloma, receiving bortezomib therapy

Aim. To study the dynamics of calculated indices [neutrophil-lymphocyte ratio (NLR); systemic inflammation index (SIV)] and biomarkers of systemic inflammation [interleukin-1β (IL-1β); high-sensitivity C-reactive protein (hsCRP)], parameters of the structure-and-function state of the myocardium and intracardiac hemodynamics, and their relationship in patients newly diagnosed with multiple myeloma (MM) at the onset of the disease and after 6 courses of chemotherapy (CT) containing the proteasome inhibitor bortezomib.Material and methods. This prospective study included 30 patients aged 63.8±10.0 years diagnosed with MM; 17 (56.7 %) of them were men. The following tests were performed for all patients: measurement of IL-1β and hsCRP, calculation of the inflammation indexes NLR and SIV, transthoracic echocardiography before and after 6 courses of bortezomib-containing CT. At the time of study completion, 9 patients dropped out due to reasons not related to cardiovascular complications of CT.Results. The antitumor therapy was associated with increases of immune-inflammation indexes: NLR increased from 1.54 [1.02; 1.83] to 2.9 [1.9; 4.35] (p=0.009) and SIV increased from 402.95 [230.5; 534.0] to 1102.2 [453.1; 1307.9] (р=0.014). IL-1β increased from 5.15 [4.05; 5.77] to 6.22 [5.66; 6.52] pg/ml remaining within the reference range (p=0.142) whereas hsCRP decreased from 1.02 [0.02; 2.71] to 0.02 [0.02; 0.82] IU/l (p=0.138). Statistically significant changes in parameters of heart remodeling and clinical picture of cardiovascular complications were not observed. A correlation analysis showed significant inverse correlations of hsCRP with left ventricular ejection fraction (LV EF) (r= –0.557; p=0.003), the number of plasma cells (PC) with LV EF (r= –0.443; p=0.023), and a direct correlation of the number of PC with hsCRP (r=0.433; p=0.022).Conclusion. During the study, the accepted criteria for cardiotoxicity of bortezomib-containing chemotherapy in patients with MM, were not met. The identified correlations between the level of markers for acute inflammation, indexes of intracardiac hemodynamics, and the immediate MM substrate may indicate the role of chronic low-intensity inflammation in the pathogenesis of myocardial remodeling in patients with MM. This necessitates further studies on larger samples of patients to assess the prognostic significance.

Abstract 14483: Myeloid Cell Derived IL1b Contributes to Pulmonary Vascular Remodeling in Heart Failure With Preserved Ejection Fraction

Introduction: Pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF) is a common and highly morbid syndrome, but mechanisms driving PH-HFpEF are poorly understood. Hypothesis: We sought to determine whether a well-accepted murine model of HFpEF also displays features of PH, and we sought to identify pathways that might drive early remodeling of the pulmonary vasculature in HFpEF. . Methods: Eight-week-old male and female C57BL/6J mice received either L-NAME and high fat diet (HFD) or control water and diet for 2, 5, and 12 weeks. Db/db mice were studied as a second model of HFpEF. Early pathways regulating PH were identified by bulk and single cell RNA sequencing. Findings were confirmed by immunostain in lungs of mice or lung slides from clinically performed autopsies of PH-HFpEF patients. ELISA was used to verify IL1β in mouse lung, mouse plasma, and also human plasma from PH-HFpEF patients obtained at the time of right heart catheterization. Clodronate liposomes and an anti-IL1β antibody were utilized to deplete macrophages and IL1β, respectively, to assess their impact on pulmonary vascular remodeling in HFpEF in mouse models. Results: L-NAME/HFD treated mice developed PH, small vessel muscularization, and right heart dysfunction. Inflammation-related gene ontologies were over-represented in bulk RNA sequencing analysis of whole lungs, with an increase in CD68 + cells in both murine and human PH-HFpEF lungs. Cytokine profiling showed an increase in IL1β in mouse and human plasma. Finally, clodronate liposome treatment in mice prevented PH in L-NAME/HFD treated mice, and IL1β depletion also attenuated PH in L-NAME/HFD treated mice. Conclusions: We report a novel model for the study of PH and right heart remodeling in HFpEF, and we identify myeloid cell derived IL1β as an important contributor to PH in HFpEF.

Abstract 15205: miR-132 Inhibition Improves Myocardial Strain in a Large Animal Model of Chronic Adverse Remodeling

Background: MicroRNAs (miRNAs) are transcriptional regulators and essential drivers of heart failure (HF). The miR-132 is necessary and sufficient to progress adverse cardiac remodeling. The strong effects are exhibited by, amongst others, cardiomyocyte hypertrophy and calcium signaling impairment. Treatments directly targeting the roots of the disease are scarce, but miR-132 inhibition by CDR132L, a rationally designed synthetic oligonucleotide, significantly improves cardiac dysfunction in HF early after myocardial infarction (MI). Rational: The aim of the current study was to gain further data on myocardial function and efficacy of CDR132L by analyzing left ventricular (LV) and atrial (LA) wall motion by serial cardiac magnetic resonance (cMRI) strain imaging in a clinically relevant large animal (pig) model of chronic HF. Methods and Results: Mangalica pigs (n=15) were randomized 1-month post-MI, initiated by left anterior descending artery occlusion followed by reperfusion as a chronic model of post-MI HF. Animals received CDR132L over 5 months by monthly intravenous treatments with 5 mg/kg. LV and LA strain parameters were deteriorated after MI over time but significantly ameliorated by CDR132L treatment, compared to placebo. Strain parameters showed significant correlations with pharmacodynamic measures such as left-ventricular ejection fraction, NT-proBNP and cardiac interstitial fibrosis in remodeling hearts 6 months post-MI. Conclusions: LV and LA motion and contractility were improved by repeated dosing of CDR132L with monthly frequency in a large animal model of chronic post-MI HF. The results highlight the translational value and usability of MRI-based cardiac strain imaging in HF drug development and support further clinical development of CDR132L.

Abstract 18612: Stem Cell-Derived Extracellular Matrix as a Treatment for Cardiac Remodeling in Post-MI Hearts: A Pilot Study

Introduction: Post-myocardial infarction (post-MI) cardiac remodeling and decline in cardiac function remains a vexing problem. Tissue engineered extracellular matrix (ECM) has been used in the past but was restricted by the manufactured structure and mechanical limitations. Here, we use a novel ECM substrate generated by self-assembled cells seeded into spherical molds, that are devoid of the hierarchical structure of ECM fabrication, as a treatment for post-MI cardiac remodeling. Hypothesis: Intramyocardial (IM) injection of ECM particles will result in improved cardiac function and reduced infarct size in post-MI hearts. Methods: Human bone marrow mesenchymal stem cells were cultured and ECM particles were isolated, seeded into micro molds, purified, and characterized. ECM particles were suspended at a concentration of 63,400 particles per mL to create an injectable solution. WT mice underwent left anterior descending (LAD) artery ligation followed by IM injection of 10uL of saline control (n=3) or ECM solution (n=7) to the infarcted area (Figure 1A). Mice then underwent post-operative day 3 (POD 3) and POD 7 echocardiogram to determine changes in cardiac function. Results: There was a trend in improving ejection fraction (EF) in ECM injection group compared to control injection in post-MI at POD 3 while no difference was seen at POD 7 (Figure 1B). No difference in fractional shortening (FS) was observed at POD 3 or POD7 (Figure 1C). Echos at POD 14, POD 21, and POD 28 and additional animals will be added to increase study power. Conclusion: IM injection of ECM trends towards mitigating decline in EF at POD3 and does not affect FS in post-MI hearts. These results are likely underpowered (n=3 versus n=7) and may be a portent of significant myocardial protection post-MI. Our ongoing studies (n=10 per group) investigating the mechanisms by which ECM injections assuage ischemic insult to the myocardium may represent a future strategy for clinical therapy.