bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostic findings in relatives to victims of sudden unexplained death or non-autopsied possible sudden cardiac death
Authors: Dalgaard C.V , Hansen B.L , Jacobsen E.M , Kjerrumgaard A , Tfelt-Hansen J , Weeke P.E , Winkel B.G , Christensen A.H , Bundgaard H 
Published: November 2020

Abstract

Introduction
Sudden cardiac death (SCD) may be caused by several inherited cardiac diseases and screening and treatment of relatives may be lifesaving. Sudden unexplained death (SUD) victims have been autopsied, whereas non-autopsied possible SCD (pSCD) victims are only filtered on manner of death and medical records. Screening of relatives may identify an inherited cardiac disease.

Purpose
To assess the diagnostic yield at initial evaluation and during follow-up of relatives to SUD and pSCD victims. Furthermore, to evaluate the outcome in the relatives.

Methods
We retrospectively included first-degree relatives to SUD and pSCD victims referred to our tertiary center from 2005 to 2018. Probands with known antemortem inherited cardiac disease were excluded. Data from systematic screening and routine follow-up of the relatives were registered.

Results
We included 371 first-degree relatives from 187 families: 276 SUD relatives (age at initial evaluation 35±17 years, 54% men;) and 95 pSCD relatives (age at initial evaluation 40±15 years, 51% men). The diagnostic yield among SUD families was 18%, among pSCD families 13% (p&gt;0.05 between groups). The diagnoses in SUD families were mainly channelopathies (68%), whereas the pSCD families were diagnosed with cardiomyopathies, channelopathies, and premature ischemic heart disease (Figure 1). The vast majority of diagnosed families (93%) were diagnosed at the initial evaluation and only two families were diagnosed during the mean follow-up of 5.4 years. During follow-up, 57 (15%) relatives had a cardiac-related hospitalization, 12 (3%) relatives had a cardiac device implanted, three (1%) relatives died of non-cardiac causes, and one (0.5%) relative had a myocardial infarction. There was no significant difference in cardiac event rates between the SUD and pSCD groups (all p&gt;0.05).

Conclusion
One in 6–7 families with SUD or pSCD victims obtained a diagnosis based on screening of relatives; we mainly diagnosed channelopathies in SUD families and a broader spectrum of inherited cardiac disease in the pSCD families. The majority of affected relatives was diagnosed at the initial evaluation and clinical follow-up may not be warranted in all relatives with normal findings at initial screening.
Figure 1. Family diagnoses in categories, n (%)

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): The Capital Regions Research Foundation and The A.P. Moeller Foundation.
ZEB2 regulates a transcriptional network of calcium-handling genes in the injured heart
Authors: Gladka M , De Leeuw A , Kohela A , Molenaar B , Versteeg D , Kooijman L , Van Geldorp M , Van Rooij E 
Published: November 2020

Abstract

Intracellular calcium (Ca2+) overload is known to play a critical role in the development of cardiac dysfunction. Despite the remarkable progress in managing the progression of the disease, the development of effective therapies for heart failure (HF) remains challenging. Therefore, it is of great importance to understand the molecular mechanisms that maintain calcium level and contractility in homeostatic conditions. Here we identified a transcription factor ZEB2 that regulates the expression of numerous contractile and calcium-related genes.
Zinc finger E-box-binding homeobox2 (ZEB2) is a transcription factor that plays a role during early fetal development and epithelial-to-mesenchymal transition (EMT); however, its function in the heart remains to be determined. Recently, we found that ZEB2 is upregulated in murine cardiomyocytes shortly after an ischemic event, but returns to baseline levels as the disease progresses. Gain- and loss-of-function genetic mouse models revealed the necessity and sufficiency of ZEB2 to maintain proper cardiac function after ischemic injury. We show that cardiomyocyte-specific ZEB2 overexpression (Zeb2 cTG) protected from ischemia-induced diastolic dysfunction and attenuated the structural remodeling of the heart. Moreover, RNA-sequencing of Zeb2 cTG hearts post-injury implicated ZEB2 in the regulation of numerous calcium-handling and contractile-related genes when compared to wildtype mice. Mechanistically, ZEB2 overexpression increased the phosphorylation of phospholamban (PLN) at both serine-16 and threonine-17, implying enhanced activity of the sarcoplasmic reticulum Ca2+-ATPase (SERCA2A), thereby augmenting contractility. Improved cardiac function in ZEB2-overexpressing hearts correlated with higher expression of several sarcomeric proteins like myosin-binding protein C3 (MYBPC3), desmin (DES) and myosin regulatory light chain 2 (MYL2) further contributing to the observed protective phenotype. Furthermore, we observed a decrease in the activity of Ca2+-depended calcineurin/NFAT signaling, which is the main driver of pathological cardiac remodeling. Conversely to Zeb2 cTg mice, loss of ZEB2 from cardiomyocytes perturbed the expression of calcium- and contractile-related proteins and increased the activity of calcineurin/NFAT pathway, exacerbating cardiac dysfunction. Together, we show that ZEB2 is a central regulator of contractile and calcium-handling components, consequently mediating contractility in the mammalian heart. Further mechanistic understanding of the role of ZEB2 in the regulation of calcium homeostasis in cardiomyocytes is a critical step towards the development of improved therapies for various forms of heart failure.

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): DR. E. Dekker from Dutch Heart Foundation
Inhibition of the activin receptor improves cardiac remodelling in the ercc1 mouse model of accelerated ageing
Authors: Clavere N , Patel K , Kevei E , Boateng S.Y 
Published: November 2020

Abstract

Introduction
In the heart, ageing is associated with pathological remodelling due to an increase of DNA damage, oxidative stress and fibrosis that impairs function, often leading to heart failure. Ageing is also associated with activation of the activin signalling pathway which contributes to cardiac dysfunction. Previous studies have shown that inhibition of the activin signalling pathway preserves cardiac function during aging. However, the beneficial effects of this inhibition in cardiac disorders such as accelerated ageing remain unknown.

Purpose
We hypothesized that inhibition of the activin receptor would be beneficial for the pathological cardiac phenotype of the Ercc1Δ/− mouse model of accelerated ageing.
We aimed to determine the cardiac phenotype of the Ercc1 mouse, and how inhibition of activin signalling affects cardiac remodelling using immunological and biochemical analysis.

Methods
Using immunohistochemical staining, we investigated the cardiac phenotype in 16 week old Ercc1Δ/− progeric and Ercc1+/+ wildtype mice (n=4–6) with or without soluble activin receptor injections from the week 7 (sActRIIB, 10mg/kg). The Ercc1Δ/− mouse displays a deficiency in DNA repair, leading to an accelerated ageing phenotype. Experimentally, injections of the myostatin /activin antagonist called the soluble ActRIIB receptor trap (sActRIIB) can be used to pharmacologically target the activin signalling pathway.

Results
In Ercc1Δ/− mice at 16 weeks there was a 50% decrease in the heart weight in comparison to Ercc1+/+ wildtype mice (175±13 vs 85±4), (p&lt;0.001). Activin inhibition did not have any effect on the heart weight. To determine the extent of DNA damage, cardiac tissue was stained for γH2Ax. γH2Ax accumulates at double stranded DNA breaks where histone 2A becomes phosphorylated. Ercc1Δ/− mice displayed a 20% increase in double stranded DNA breaks in comparison to the Ercc1+/+ wildtype (0.6±0.5 vs 22.5±2.5 vs 15.8±0.7), (p&lt;0.01). Activin inhibition led to a significant 5% decrease (p&lt;0.05). Oxidative stress was determined by dihydroethidium staining. Ercc1Δ/− mice showed a 30% increase in oxidative stress (33.33±3 vs 49.98±3 vs 36.19±3), (p&lt;0.05). Activin inhibition reversed this increase of oxidative stress in Ercc1Δ/− mice (p&lt;0.05). Finally, cardiac fibrosis was assessed using picrosirius red staining. No differences were observed between the Ercc1Δ/− progerics and Ercc1+/+ wildtype mice, while activin inhibition led to a 50% decrease (4.9±0.3 vs 7.7±1.3 vs 2.9±0.1), (p&lt;0.01). Interestingly, Ercc1Δ/− mice display thicker cardiac interstitial collagen I (1.3±0.01 vs 1.4±0.05 vs 1.3±0.01), (p&lt;0.05). Activin inhibition also reversed this increased interstitial collagen (p&lt;0.05).

Conclusion
Inhibition of activin receptor signalling brings beneficial effects to the Ercc1Δ/− cardiac phenotype by attenuating oxidative stress, DNA damage and fibrosis.

Funding Acknowledgement
Type of funding source: None
PKG oxidation at Cys42 amplifies mTORC1 activation to worsen hypertrophic heart disease
Authors: Oeing C.U , Dunkerly-Eyring B , Pieske B , Kass D , Ranek M 
Published: November 2020

Abstract

Rationale
Protein kinase G-1a (PKG1a) phosphorylation of tuberous sclerosis complex 2 (TSC2, or tuberin) at serine 1365 (S1365) potently suppresses mTORC1 activation. This results in greater autophagy and limits pathological hypertrophy myocytes and the heart. Cardiac stress also induce oxidation of PKG1a between cysteine 42 residues in homo-monomers, which reduces cardioprotection.

Objective
We tested the hypothesis that pathological mTORC1 activation is potently amplified by concomitant PKG1a C42-oxidation, and that this is countered by stimulating soluble guanylyl cyclase-1 (GC-1).

Methods and results
In mice expressing only C42-redox inhibited PKG1a (PKG1aCS), pressure-overload (PO) induces markedly less mTORC1 activation, increasing autophagic flux and reducing protein aggregation, hypertrophy, and dysfunction compared to PO in PKG1aWT mice. Similar results were obtained in cardiomyocytes exposed to endothelin-1. Protection against PO in PKG1aCS mice was similar to PKG1aWT co-treated with the mTORC1-inhibitor everolimus. TSC2 S1365 phosphorylation increased more in PKG1aCS than PKG1aWT myocardium after PO. Knock-in mice with TSC2 S1365A and PKG1aCS mutations, to prevent TSC2 phosphorylation by PKG1a displayed amplified mTORC1, cardiodepression, and mortality after PO as compared to PKG1aCS. Lastly, the marked disparity between PKG1aWT and PKG1aCS PO phenotype for TSC2 S1365 phosphorylation, mTORC1 activation, and cardiac dysfunction is overcome by BAY-602770, a direct stimulator of GC-1.

Conclusion
Oxidant-induced PKG1a C42 dimerization blunts its attenuation of mTORC1 activity by reducing TSC2 S1365 phosphorylation, thereby contributing to inadequate autophagy and worsened hypertrophic dysfunction. This is ameliorated by direct GC-1 stimulation.

Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): DFG
Basic mechanism of atrial and ventricular arrhythmia suppression by heavy ion irradiation in hypercholesterolemic elderly rabbits
Authors: Amino M , Kabuki S , Kunieda E , Sakai T , Sakama S , Ayabe K , Yagishita A , Shimokawa T , Yamazaki M , Ikari Y , Kodama I , Yoshioka K 
Published: November 2020

Abstract

Background
Recent development of electrophysiology-guided noninvasive cardiac radioablation therapy for ventricular tachycardia attracts a great deal of attention as a novel antiarrhythmic strategy (Robinson CG, Circulation 2019). As to underlying mechanisms, however, much remains to be clarified. We reported before that a single targeted heavy ion irradiation (THIR 15Gy) to rabbit hearts increased connexin43 (Cx43) expression, and a reduction of vulnerability to ventricular arrhythmias after myocardial infarction.

Purpose
We investigated the effects of THIR on in-vivo cardiac electrophysiology and vulnerability to atrial and ventricular tachyarrhythmias in aged rabbits with hypercholesterolemia.

Methods
Sixteen three-year old rabbits were fed with high fat/cholesterol chow (0.5% cholesterol and 10% coconut oil) for 14 weeks. A single THIR 15Gy was applied to 8 rabbits (HC+THIR) with a heavy ion medical accelerator. Eight rabbits without THIR were used as control (HC).

Results
Serum cholesterol levels in the HC and HC+THIR were 1545+386 and 1569+328 mg/dl (n=8, NS). Atrial (P-wave) late potential in signal-averaged ECG in HC+THIR showed a significantly larger root mean square voltage (RMS) than those in HC (12+0.5 vs. 2+0.5μV, n=4, p&lt;0.01). Ventricular late potentials in HC+THIR showed significantly less fQRS-D than HC (81+5 vs. 89+7 ms); less LAS40 (21+7 vs. 30+4 ms), and larger RMS (99+27 vs. 44+13μV) (n=4, p&lt;0.04). Atrial tachycardia or fibrillation (AT/AF) was induced spontaneously or by programmed/burst pacing of the left atria (LA) in 4 out of 4 HC, whereas in only 1 out of 4 HC+THIR. Ventricular tachycardia or fibrillation (VT/VF) was induced spontaneously or by programmed pacing or left stellate stimulation in 4 out of 4 HC rabbits, whereas in only 1 out of 4 HC+THIR. Immunolabeled Cx40 densities in LA and RA tissue from HC+THIR rabbits were significantly higher than those from HC rabbits by 44% and 60%, respectively (n=4, p&lt;0.01). Comparable upregulation of immunoreactive Cx43 was observed in LV and RV tissue from HC+THIR rabbits. Sympathetic nerve densities in LA, RA, LV and RV tissues, which was labeled with anti-neuronal growth-associated protein 43 (GAP43) antibody and tyrosine hydroxylase (TH) antibody were both significantly less in HC+THIR than those in HC.

Conclusion
These results suggest that THIR may improve cardiac conductivity of HC rabbits in favor of reduction of vulnerability to atrial and ventricular tachycardia/fibrillation, and that this antiarrhythmic effect is attributed to upregulation of gap junction protein (Cx40 and Cx43) and in part to prevention of sympathetic nerve sprouting.

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): KAKENHI KIBAN (C) 53020
Bioenergetic and metabolic impairments in Duchenne Muscular Dystrophy (DMD) patients' iPSC-derived cardiomyocytes
Authors: Willi L , Agranovich B , Abramovich I , Freimark D , Arad M , Gottlieb E , Binah O 
Published: November 2020

Abstract

Introduction
DMD, an X-linked muscle degenerative fatal disease, is caused by mutations in the dystrophin gene. Dilated cardiomyopathy (DCM) is a major cause of morbidity and mortality in DMD patients. Treatments for DCM in DMD are limited to steroids and standard heart failure medications such as β-blockers and ACE-inhibitors, and therefore novel therapeutic modalities are urgently needed.

Purpose
We hypothesized that dystrophin mutations in DMD lead to cardiomyopathy-causing bioenergetic/metabolic impairments, which can be therapeutically targeted for improving cardiac function.

Methods
Induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CMs) were generated from healthy volunteer and 3 DMD patients: young male (YM), adult male (AM) and adult female (AF). We investigated the bioenergetics, electrophysiology, mitochondrial and metabolic features of healthy and DMD iPSC-CMs using the Seahorse Flux analyzer, patch clamp, confocal fluorescence microscopy and Liquid chromatography mass spectrometry (LC-MS) technologies, respectively.

Results
To test the hypothesis, we measured respiration and glycolytic rates of healthy and DMD iPSC-CMs. Compared to healthy iPSC-CMs, in both AM and AF DMD, but not in YM DMD cardiomyocytes, there was a 75% decrease in ATP production, and 80% and 45% decrease in basal respiration, respectively. In agreement with the healthy-like bioenergetic status of YM, the iPSC-CMs showed no arrhythmias, in contrast to the prominent arrhythmias in AM and AF cardiomyocytes. To determine whether the impairment in the phosphorylation pathway (OXPHOS) affects glycolysis, we measured the cardiomyocytes' response to glycolytic stress test. These experiments showed that the glycolytic rates were similar in healthy and DMD iPSC-CMs. In agreement with impaired OXPHOS, mitochondrial activity measured by 3D life confocal microscopy was attenuated in the DMD male by 35%, compared to healthy cardiomyocytes. Furthermore, the metabolomic LC-MS analyses demonstrated significant differences in metabolite levels in YM, AM and AF DMD iPSC-CMs relative to healthy iPSC-CMs. For example, compared to healthy iPSC-CMs, there was a dramatic fall to undetected levels in phosphocreatine in both AM and AF, but not in YM DMD, indicating a dysfunctional phosphocreatine energy system.

Conclusions
DMD iPSC-CMs exhibit bioenergetic/metabolic impairments, which constitute novel targets for alleviating the cardiomyopathy in DMD patients.

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): ISF - Israel Science Foundation
Age alters peripheral vascular endothelial function without affecting coronary flow reserve in healthy volunteers
Authors: Bouly M , Bourguignon M.P , Ley S , Xuereb L , Bernhardt P , Tyl B 
Published: November 2020

Abstract

Background
Age is a key risk factor contributing to vascular endothelial dysfunction. Whether the impact of ageing is uniform on various vascular beds is unknown. Endothelial function is classically evaluated by the brachial flow mediated dilatation (FMD) after a brief occlusion which mainly involves nitric oxide (NO) production. However, FMD measurement, requiring highly trained technicians, has been shown to be associated with a high degree of variability. Endothelial function could be also assessed by cutaneous iontophoresis combined with Laser Doppler. By contrast to FMD, this method is easily done by nurses and shows less variability. In parallel, myocardial imaging allows measurement of coronary flow reserve (CFR) coupled with an adenosine challenge leading to both a NO release and a modulation of potassium channels.

Purpose
The aim of this study was to determine the impact of ageing on vasodilation of peripheral (cutaneous) and coronary blood vessels in healthy volunteers.

Methods
This prospective single German center study enrolled 75 healthy non-smoking normotensive volunteers, taking no medication. They were divided into three age-subgroups (n=25/group): 18–30, 50–59, and 60–70 years (women: 54, 27 and 23%, respectively). All subjects underwent clinical and laboratory evaluation.
Peripheral endothelial function, expressed in cutaneous blood flow (delta CBF), was assessed through cutaneous microcirculation dilation by the non-invasive method using Laser Doppler Speckle Contrast Imaging (LSCI, Perimed) coupled with iontophoresis to locally deliver 125 nmoles of acetylcholine (Ach). The CFR was determined by cardiac magnetic resonance (CMR) coupling with an intravenous infusion of adenosine at 140 μg/kg/min for at least 3 minutes.

Results
Age was associated with a 23% reduction of peripheral endothelial function (delta CBF, p=0.005) in the elderly group (60–70y) vs. the younger one (18–30y) (median: 56.4 vs. 73.6). By contrast, calculated CFR was unchanged (median: 4.1 vs. 4.2, p=0.38). No relationship was observed between peripheral endothelial function (delta CBF) and CFR (r=0.01, p&gt;0.97) in healthy volunteers.

Conclusion
In healthy volunteers, ageing is associated with a progressive peripheral but not with a coronary vascular dysfunction. This suggests that the impact of age on endothelial dysfunction depends on different vascular beds. Peripheral endothelial function assessment does not predict coronary vascular function in healthy volunteers.

Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Servier
Systemic microvascular endothelial dysfunction is associated with reduction of left ventricular ejection fraction in chronic Chagas disease patients
Authors: Kasal D , Britto A , De Lorenzo A , Verri V , Tibirica E 
Published: November 2020

Abstract

Introduction
Chagas disease (CD) affects millions of patients around the world, many of whom may develop cardiovascular complications, including heart failure and stroke. Notwithstanding, little is known about the effects of CD in the reactivity of the systemic microcirculation.

Purpose
The present study aims to compare the microvascular reactivity (MR) of a group of patients in the chronic phase of CD with healthy volunteers, matched for sex and age. In addition, we sought to evaluate the association between MR and left ventricular ejection fraction (LVEF) in CD patients.

Methods
Systemic microvascular flow and endothelium-dependent vasodilation were assessed using laser speckle contrast imaging, coupled with acetylcholine (Ach) iontophoresis in the forearm skin. Vascular reactivity data were expressed as area under the curve (AUC) of Ach-induced vasodilation. Anthropometry, medications, biochemistry, and echocardiographic data were obtained from medical records.

Results
Thirty-six patients were compared to 25 healthy individuals (controls). Ach-induced vasodilation was higher in controls, when compared to patients (maximum increase of microvascular flow from baseline of 106% and of 48% respectively, P&lt;0.0001; Mann Whitney test). There was a significant association between LVEF, stratified into quartiles, and MR (P value for linear trend = 0.002; one way ANOVA, Figure 1). In addition, there was no difference in MR between CD patients with normal LVEF and the control group. In CD patients, MR was independent of the presence of arterial hypertension or diabetes.

Conclusion
We have shown that the reduction of MR is associated with a decrease of LVEF in a group of chronic CD patients. The results were not affected by comorbidities, such as hypertension or diabetes. The evaluation of systemic endothelial function may be useful to tailor therapeutic and preventive approaches, targeted at systolic left ventricular failure associated with chronic CD cardiomyopathy.
Figure 1

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro