bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation-induced electrophysiological remodelling in neonatal rat ventricular cardiomyocytes
Authors: Mages C , Gampp H , Rahm A K , Ullrich N D , Seidensaal K , Rhein B , Debus J , Frey N , Thomas D , Lugenbiel P 
Published: October 2022

Abstract

Background
Ventricular tachycardia (VT) carries a relatively high risk of recurrence and significantly impacts patients' quality of life, despite state of the art treatment including antiarrhythmic drug therapy and catheter ablation. Cardiac stereotactic body radiotherapy (SBRT) has emerged as a promising non-invasive treatment option for refractory VT. A marked reduction in VT episodes is observed within days of treating high-risk patients with a single fraction SBRT. The cellular mechanisms underlying the clinically demonstrated antiarrhythmic effect are still poorly understood. Radiation-induced fibrosis is observed several months after irradiation, suggesting other mechanisms that explain the immediate benefit of radiotherapy on the VT substrate.

Purpose
We hypothesized that early antiarrhythmic effects of single-fraction radiation are produced by direct molecular and functional electrophysiological changes, independent of fibrosis. Our aim was to investigate the effects of 20 Gy ionizing photon radiation on the electrophysiology of ventricular neonatal rat cardiomyocytes at time periods from 24 hours to 96 hours after irradiation.

Methods
Ventricular neonatal rat cardiomyocytes were isolated, cultivated for 24 to 96 hours and then exposed to photon beam with a single dose of 20 Gy. Expression changes of ion channels, calcium handling proteins and structural proteins affecting cellular electrophysiology were assessed via RT-qPCR and Western blotting. Beat frequency was evaluated by video analysis and action potentials (APD) were recorded using the whole-cell voltage clamp technique in current-clamp mode. Intracellular calcium transients in Fura-2 AM loaded cardiomyocytes were recorded with an IonOptix recording system.

Results
Irradiation lead to significant changes in the mRNA and protein level of ion channels, with most distinct changes being observed 96h after radiation. Increased mRNA and protein expression of (Cav1.2) and of the potassium channels Kcnd3 (Kv4.3), Kcnh2 (Kv11.1), Kcnq1 (Kv7.1), Kcnk2 (K2P2.1) and Kcnj2 (Kir2.1) was observed. Additionally, Connexin 43 (Cx43) was upregulated. Irradiated cardiomyocytes showed a significant increase in beat rate over time. APD was significantly shortened, with a significantly increased upstroke velocity. Regarding calcium handling, significant upregulations of Ryr2 (RYR2) and Slc8a1 (NCX) transcript and protein level was detected. Additionally, calcium handling properties were altered.

Conclusion
Our results suggest that acute irradiation effects are associated with electrophysiological remodelling in cardiomyocytes. Changes of cellular ion channel expression and calcium homeostasis lead to normalization and shortening of heart-failure associated APD prolongation. These results reveal new insights into acute antiarrhythmic effects on cardiomyocytes after SBRT-therapy.

Funding Acknowledgement
Type of funding sources: None.
Plasma miR-451a predicts atrial fibrillation recurrence after pulmonary vein ablation
Authors: Cebro-Marquez M , Vilar-Sanchez M E , Gonzalez-Melchor L , Garcia-Seara J , Martinez-Sande J L , Fernandez-Lopez X A , Martinez-Monzonis M A , Gonzalez-Juanatey J R , Rodriguez-Manero M , Lage-Fernandez R , Moscoso Galan I 
Published: October 2022

Abstract

Background/Introduction
Atrial fibrillation (AF) is the most common sustained arrhythmia diagnosed in European countries. Several studies have shown that catheter ablation is a more effective treatment than antiarrhythmic drugs and should be prioritised in symptomatic patients. However, AF recurrence after catheter ablation remains a challenge. MiRNAs have been identified, in recent years, as epigenetic modulators in numerous biological processes, including cardiac electric conduction. MiRNAs can be easily detected in the circulation, making them attractive as potential biomarkers for risk stratification in AF patients.

Purpose
Our purpose is to find a miRNA able to predict the AF recurrence after catheter ablation.

Methods
44 patients submitted to catheter ablation were consecutively recruited and classified based on recurrence after a follow up of 12 to 48 months. Peripheral and left atrium blood samples were collected before catheter ablation. Human Cardiovascular Disease miScript miRNA PCR Arrays were performed to analyse 84 miRNAs altered in cardiovascular disease. Significant miRNAs changes in ΔCt levels were assessed using Two-way ANOVA and post hoc Tukey tests. Simple logistic regression analysis was performed to analyse association to AF recurrence. KEGG pathway enrichment analysis was performed to identify the most enriched targets and pathways involved in AF recurrence.

Results
In our cohort, overall recurrence rate was 47.7%. qPCR expression analysis showed increased levels of miR-328-3p and decreased levels of miR-486-5p in recurrent patients, both in peripheral as well as left atrial blood. Our results also showed decreased levels of miR-let-7b-5p and miR-451a in recurrent patients, but selectively regulated in peripheral and atrial blood, respectively (Figure 1). Simple logistic regression analysis showed a significant association between blood atrial levels of miR-451a and AF recurrence (Figure 2A). KEGG pathway enrichment analysis showed that miR-451a could be involved in epigenetic regulation of myocardial electromechanic integrity (Figure 2B).

Conclusion
Expression analysis of atrial blood miR-451a levels, prior to catheter ablation, could be a good a risk stratifier of recurrence.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): IN607A2019/02. Xunta of Galicia. Grants for the consolidation and structuring of competitive research units in the universities of the Galician University System, in the public research organizations of Galicia and in other entities of the Galician R&D System 2019
Empagliflozin alleviates diabetic cardiomyopathy via inhibiting excessive autophagy and adverse remodeling in type 1 diabetic mice
Authors: Madonna R , Moscato S , Cufaro M , Pieragostino D , Mattii L , Del Boccio P , Ghelardoni S , Zucchi R , De Caterina R 
Published: October 2022

Abstract

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular mortality in patients with and without diabetes mellitus, but underlying mechanisms remain unclear. Autophagy is an important cardioprotective mechanism under acute stress conditions, but excessive autophagy can accelerate myocardial cell death leading to autosis. In this study we evaluated the role of empagliflozin (EMPA) against cardiac injury in streptozotocin (STZ)-induced diabetic mice, and assessed underlying mechanisms.
EMPA (10 mg/kg/die)-treated diabetic male mice had a lower number of TUNEL-positive apoptotic cells (%TdT+ 4.9±2, p&lt;0.05), lower percentage of SA-β-gal positive senescent cardiac area (%SA-β-gal 7.9±1, p&lt;0.05), lower fibrotic area (%picrosirius red 0.15±0.06, p&lt;0.05), lower autophagy (%green fluorescence 2.3±0.6, p&lt;0.01), compared to diabetic mice (%TdT+ 4.9±2; %SA-β-gal 10±2; %picrosirius red fibrotic area 0.24±0.08; %green fluorescence autophagic area 3.98±0.5). Proteomics analysis of cardiac tissue showed downregulation of apoptosis, necrosis and 5' adenosine monophosphate-activated protein kinase (AMPK) pathways, along with upstream activation of vascular endothelial growth factor and sirtuins in the heart of EMPA+STZ treated mice compared to STZ mice. Since activation of sirtuins leads to modulation of cardiomyogenic transcription factors, we analyzed total expression of serum response factor (SRF), myocardin and myocardin-related transcription factor (MRTF), and DNA binding activity of SRF by electromobility shift assay. While EMPA only increased MRTF, EMPA (2.2±0.01, p&lt;0.01) and EMPA+STZ (2.0±0.1, p&lt;0.01) significantly increased SRF/SRE binding activity compared with STZ alone (0.5±0.01), which was paralleled by the increase in cardiac actin expression (4.06±0.1 vs 2.2±0.01, p&lt;0.01). EMPA significantly reversed STZ-induced systolic cardiac dysfunction at echocardiography, and downregulation of pS368-connexin 43 active isoform (Table). In parallel in vitro experiments, EMPA inhibited excessive autophagy in high glucose-treated cardiomyocytes by inhibiting the autophagy inducer GSK3β, leading to reactivation of transcriptional complex for cardiomyocyte contractile genes. Our results indicate that EMPA plays a cardioprotective effect by inhibiting excessive autophagy through the mTOR/AMPK axis in the mouse model of STZ-induced type 1 diabetes. EMPA also promotes cardiac reverse remodeling by inhibiting fibrosis, activates cardiac Cx43 and the promyogenic transcriptional program through the sirtuins-SRF axis (Figure 1), in the context of diabetes.

Funding Acknowledgement
Type of funding sources: None.
Histology-verified myocardial fibrosis and quantification in severe AS patients: correlation with non-invasive LV myocardial tissue assessment
Authors: Maltes S , Abecasis J , Pinto D G , Santos R R , Oliveira L , Mendes G S , Guerreiro S , Lima T , Freitas P , Ferreira A , Ramos S , Felix A , Cardim N , Gil V M , Mendes M 
Published: October 2022

Abstract

Background
Myocardial fibrosis (MF) is a common finding and a potential adverse prognostic marker in several cardiac diseases, including in severe aortic stenosis (AS). While histological analysis obtained through endomyocardial biopsy remains the gold-standard for MF assessment, non-invasive cardiac imaging may offer surrogate biomarkers for fibrosis. We tried to assess the correlation between MF quantification at histopathology and cardiac magnetic resonance (CMR)-derived tissue characterization data in patients with severe AS.

Methodology
Single-center prospective cohort enrolling 71 patients with severe symptomatic high-gradient AS undergoing surgical aortic valve replacement (SAVR) (mean age 71±9 years; 49% male, mean valvular transaortic gradient 60±20 mmHg; mean left ventricle [LV] ejection fraction 58±9%). Those with past history of myocardial infarction or cardiomyopathy were excluded. All patients underwent pre-operative CMR study with LV tissue characterization and quantification. Normal T1 mapping value was defined as &gt;1021ms as per center protocol. Myocardial tissue was obtained during SAVR either through myocardial biopsy at basal LV septum or harvested from surgical myectomy specimens. Masson's trichrome stain was used for collagen/fibrosis assessment. Automatic quantification was obtained at QuPathTM digital pathology software after applying a dedicated artificial intelligence algorithm on ultra-high-resolution digital slide scanning images.

Results
Histology-confirmed MF was observed in all patients (median percentage of fibrotic myocardial tissue 15% [IQR 9–22%]). Median global T1 mapping and extracellular volume (ECV) percentage was 1048ms (IQR 1027–1078) and 24% (IQR 20–30%), respectively. Late gadolinium enhancement (LGE) with a non-ischemic pattern was present in 42 patients (59%) with a median LGE mass of 5.8g [IQR 1.0–10.2]; median percentage of 3.7% [IQR 0.6–10.4]. While neither T1 mapping (global or basal LV septum), ECV nor LGE had any significant correlation with histology-confirmed MF (Figure 1) the vast majority had significantly elevated global and basal LV septum T1 mapping – 81% and 92%, respectively.

Conclusion
In this single-center prospective study, microscopic MF was present in all patients with severe symptomatic high-gradient AS, was accompanied by elevated T1 mapping values but no correlation was found between myocardial fibrosis at histopathology analysis and CMR-derived LV tissue characterization parameters. This may not only stem from sampling (single point biopsy vs. whole myocardial tissue assessment) but also from distinct evaluation of different types of fibrosis by different methods.

Funding Acknowledgement
Type of funding sources: None.
First 12-month follow-up of bioresorbable synthetic heart valves implanted in the aortic position in sheep
Authors: Vis A , De Kort B J , Szymczyk W , Van Rijswijk J W , Dekker S , Driessen R , Wijkstra N , Grundeman P F , Niessen H W M , Janssen H M , Dankers P Y W , Smits A I P M , Bouten C V C , Kluin J 
Published: October 2022

Abstract

Background
Replacement of diseased heart valves with the currently available valve prostheses has serious drawbacks. The use of bioresorbable synthetic “in situ tissue engineered” heart valve prostheses has been proposed to overcome the limitations of traditional heart valve prostheses. Such bioresorbable synthetic heart valve prostheses have been successfully tested as pulmonary valve replacements in preclinical studies, but data on aortic valve replacement is lacking. Here, we present the first in-vivo study on the long-term functionality of bioresorbable synthetic heart valves in the high-pressure circulation.

Methods
Approval for the animal studies was obtained by the Amsterdam University Medical Centres Animal Care Ethics Committee (AVD1180020197705) and are in agreement with the current Dutch law on animal experiments (WOD). We surgically implanted bioresorbable synthetic aortic valve prostheses in 20 female Swifter sheep in orthotopic position. The scheduled follow-up times were 1, 3, 6, 9 and 12 months.

Results
Fifteen sheep (75%) recovered well from the surgical valve implantation procedure and were included in this analysis. No sheep died due to valve failure. All valves remained free from active infectious endocarditis, thrombotic complications, and pathological calcification. A total of 10 valves (67%) were intact, thin and pliable and remained free from leaflet thickening, retraction and degradation up to 12 months after implantation. In most valves (67%), the scaffold remained sparsely- or unpopulated by cells during 12 months follow up. In some valves (33%), colonization of the valve scaffold was observed, however this was most often associated with partial degradation of the leaflet and leaflet thickening. In general, the degradation of the scaffold fibres was limited throughout the follow-up period.

Conclusion
We are the first to evaluate in vivo bioresorbable synthetic heart valves in aortic position. While valves remained functional, the study also serves as a starting point to further optimize scaffold and neotissue development for heart valve replacement in the high-pressure environment.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): 1. Cardiovasculair Onderzoek Nederland (grant number CVON2012-01)2. Netherlands Organization for Scientific Research (024.003.013)
Specific gene domains most commonly affected by CHIP-driver mutations predicting mortality in severe aortic stenosis after transcatheter aortic valve implantation
Authors: Mas-Peiro S , Abou-El-Ardat K , Pergola G , Berkowitsch A , Meggendorfer M , Rieger M , Vasa-Nicotera M , Dimmeler S , Zeiher A 
Published: October 2022

Abstract

Background
Clonal haematopoiesis of indeterminate potential (CHIP), i.e. expanded somatic blood-cell clones in persons without any other haematological abnormalities, has been shown to predict survival in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI). DNMT3A and TET2 are the two most common CHIP-driver mutations. In patients with haematological disorders, specific domains of TET2 and DNMT3A most commonly accounting for detected mutations vary across different haematological malignancies.

Purpose
The aim of our study was to analyse the distribution of the mutated domains in CHIP-driver genes in patients with severe AS undergoing TAVI, in order to gain a mechanistic insight on its specific role in AS.

Methods
We used next-generation sequencing to identify mutated domains in DNMT3A and/or TET2 genes in 453 consecutive patients with severe AS undergoing TAVI.
The site of detected mutations in DNMT3A was classified as located to the conserved proline-tryptophan-proline-tryptophan (PWWP), zinc-finger (ADD), or methyl-transferase (MTase) domains, or to other non-coding regions. For TET2, mutations were classified as involving dioxygenase (DD) or Cys-rich (CD) domains. Only mutations that are classified as moderate-to-high based on their functional impact on the protein were considered.

Results
Out of 147 patients with a CHIP-driver mutation, 92 had DNMT3A mutations and 71 had TET2 mutations, with mutations in both genes being present in 16 patients.
MTase was the most commonly involved domain in DNMT3A (61% of cases). Other affected regions were PWWP/ADD/MTase (12%), no domain/non-coding region (11%), ADD (7%), ADD/MTase (5%), and PWWP (4%) (Figure 1). Overall, MTase mutations were found in a large majority of patients (78%). Such a “hot-spot” appears to be in line with a potential recently suggested mechanism involving DNA methylation.
Most common locations for mutations in TET2 were CD/DD (48%), followed by DD (33%), CD (15%) and no domain/non-coding region (4%) (Figure 2). Overall, mutations in DD were found in a large majority of patients (81%). TET2 appears to be involved in myeloid expansion and impaired immune function with increasing age; this could play a role in its impact on heart disorders.

Conclusion
In patients with severe AS undergoing TAVI, mutations in certain sites within the most common CHIP-driver genes (MTase domain in DNMT3A gene and CD domain in TET2 gene), appear to be mostly affected. These findings could be a first step to identify “hot spots” for mutated domains associated with severe AS requiring TAVI and suggest some potential mechanistic explanations.

Funding Acknowledgement
Type of funding sources: Other. Main funding source(s): The study was further supported by the German Center for Cardiovascular Research (DZHK).
Crosstalk between PKR1 and miR-124 is crucial for EMT regulation of tc21+epicardial mesothelial cells during cardiac development and repair process
Authors: Arora H , Mammadova A , Nebigil C 
Published: October 2022

Abstract

Background
The epicardial-mesothelial cells (EMCs) are essential regulators of cardiac growth and repairment process. The epicardial-to-mesenchymal transition (EMT) of epicardial fate determination are controlled by both cell autonomous and cardiomyocyte-originated mechanisms. Here, by using an in vitro and in vivo model of epicardial EMT, we investigated the role of miRNAs as regulators of these process and their potential targets.

Methods
EMT was induced in mice embryonic tcf21+EMCs through an angiogenic cytokine, prokineticin treatments. Cre-dependent tracing of TCF21-tm-iCRE-EMCs was utilized to abrogate prokineticin receptor-1 (PKR1) in mice epicardium. Human tcf21+ cardiac fibroblast (mainly originated from epicardial origin also utilized to study for their repairment signaling.

Results
Upon EMC-specific abrogation of PKR1 in early stages of cardiac development the TCF21-tm-iCREPKR1−/− mice exhibited 13±4% embryonic lethality due to a disconnection of epicardial cells from compact layer, failed expansion of the sub-epicardial space, and disruption of heterotypic cell interaction between epicardium and myocardium. EMT-RT profiler and enrichment analysis revealed an impaired EMT in TCF21-tm-iCREPKR1−/− hearts. Ingenuity Pathway Analysis on the EMT molecular network (e.g., Snai1, Snai2, B-catenin, N-cadherin, vimentin), specific to cardiac development and defects revealed MiR-124 as a part of this network that was inversely associated and down-stream of PKR1 in cultured Tcf21+ cells. Furthermore, protein expression of SNAIL2 was significantly downregulated in TCF21-tm-iCREPKR1−/− hearts and cultured Tcf21+ cells upon treatment with mir124 mimic. The luciferase reporter assay showed that miR124 directly targeted the 3'-untranslated region of SNAIL2 in EMCs. In a counter experiment, PKR1 gene replacement or mir124 inhibitor was able to rescue the impaired EMT-genes, and an increase in apoptosis and impaired proliferation in epicardium of embryonic TCF21-tm-iCREPKR1−/− hearts. Importantly, miRNA mimic in cultured tcf21 cells maintained epithelial features in EMCs, and increased EMT-associated transcripts and traits, such as apoptosis. In contrast, MiR124 is involved in wound healing process in tcf21+human CFs and EMCs.

Conclusion
This study shows the importance of a crosstalk between PKR1 and miR-124 with respect to EMT regulation during cardiac development and repair. Controlling fibroblast-committed EMT and pathological fibrotic remodeling is of increasing interest within the field of regenerative tissue engineering and development of interventional strategies after cardiac injury.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): Fondation de France
The role of P2Y12 in cardiovascular disease beyond atherothrombosis: P2Y12 signaling promotes emergency hematopoiesis after myocardial infarction
Authors: Seung H , Wrobel J , Wadle C , Buehler T , Chiang D , Rettkowski J , Cabezas-Wallscheid N , Hechler B , Wolf D , Duerschmied D , Idzko M , Bode C , Von Zur Muehlen C , Hilgendorf I , Heidt T 
Published: October 2022

Abstract

Background
Adenosine diphosphate (ADP) plays a pivotal role in platelet activation. The purinergic ADP-receptor P2Y12 has therefore been targeted in the treatment of cardiovascular disease (CVD) to prevent atherothrombosis (1). Beyond P2Y12 expression on platelets, purinergic receptors have also been described on hematopoietic stem and progenitor cells (LSK) (2). After myocardial infarction (MI), accelerated LSK proliferation launches emergency hematopoiesis as the driving force behind the inflammatory response to MI, increasing inflammatory cell production in the bone marrow (BM) and providing leukocyte resupply for local cell recruitment to the infarct (3). The inflammatory cascade after MI covers intricate multilayered interactions between the injured myocardium and the hematopoietic BM that still remain to be fully elucidated and may unearth novel therapeutic strategies. Whereas P2X receptors have recently been found to be involved in cell trafficking (4), the role of P2Y receptors in the hematopoietic BM have not yet been characterized.

Purpose
This study aims to characterize the influence of P2Y12 signaling on emergency hematopoiesis and cardiac remodeling after MI.

Methods
Permanent coronary ligation was performed for MI to assess BM activation, inflammatory cell composition, cardiac remodeling and function in murine global and platelet-specific P2Y12 knockout models and under pharmacological P2Y12 inhibition with prasugrel using flow cytometry, qPCR, immunohistochemistry and echocardiography. In vitro studies including colony forming unit (CFU) assays and flow cytometry allowed for investigation of ADP-dependent effects on LSK cells and intracellular pathway analysis.

Results
We identified ADP as a danger signal for the hematopoietic BM, fueling emergency hematopoiesis by promoting Akt phosphorylation and cell cycle progression. Detection of P2Y12 expression in LSK implicated a direct effect of ADP on LSK via P2Y12 signaling. P2Y12 deficiency and P2Y12 inhibition with prasugrel decelerated emergency hematopoiesis and consecutively reduced the excessive inflammatory response to MI, translating to lower numbers of hematopoietic progenitors and inflammatory cells in the blood and infarct. Ultimately, P2Y12 inhibition ameliorated chronic adverse cardiac remodeling and preserved cardiac function after MI.

Conclusion
ADP-dependent P2Y12-mediated activation of hematopoietic stem and progenitor cells in the BM promotes emergency hematopoiesis after MI and fuels post-ischemic inflammation, proposing a novel role of P2Y12 antagonists in CVD beyond atherothrombosis.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG)