bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethanol-induced atrial fibrillation results from late INa and can be prevented by ranolazine
Authors: Baier M , Mustroph J , Unsin D , Lebek S , Tarnowski D , Provaznik Z , Voigt N , Wagner S , Maier L , Neef S 
Published: November 2023

Abstract

Background
Ethanol consumption is the most important self-triggered cause of atrial fibrillation (AF). As abstinence often fails, alternative therapies are needed. CaMKII-activation upon ethanol with consecutive Ca2+-leak from the sarcoplasmic reticulum (SR) appears to be an important pathomechanism for ethanol-induced AF, but is not a druggable target. CaMKII has previously been shown to induce late sodium current (late INa) which could be proarrhythmogenic.

Purpose
We hypothesized that late INa might be involved in the development of AF upon acute ethanol exposition and that thus, the antianginal drug ranolazine (an inhibitor of late INa) could be repurposed to prevent ethanol-induced AF.

Methods
Acute effects of ethanol were investigated in vivo and in vitro as compared to vehicle. The occurrence of AF in vivo was assessed by programmed electrical stimulation in mice. To test the role of late INa, we used ranolazine in vivo and in vitro, as well as tetrodotoxin in vitro. We measured late INa and cytosolic sodium concentration, recorded stimulated action potentials and spontaneous delayed afterdepolarizations (DAD), and assessed SR Ca2+-leak by recording Ca2+-sparks. Mechanistically, we inhibited CaMKII using AIP and used NaV1.5 S571A mice to specifically investigate the role of CaMKII-mediated late INa. Human biopsies were acquired during surgery and were used for cell isolation or chunk incubation.

Results
Ethanol acutely induced late INa, sodium overload, SR Ca2+-leak and delayed afterdepolarizations in isolated atrial cardiomyocytes, as well as atrial fibrillation in vivo (10 of 10 mice). All of these cellular ethanol effects were prevented by pharmacologic inhibition of late INa. Importantly, ranolazine prevented the development of AF upon ethanol exposure in vivo. Mechanistically, CaMKII-activation and, accordingly, CaMKII-dependent NaV1.5 phosphorylation (S571) were increased by ethanol exposure. Indeed, the phosphoresistant NaV1.5 S571A mutation prevented late INa, SR Ca2+-leak and in vivo AF upon ethanol, demonstrating a critical role of CaMKII-mediated NaV1.5 phosphorylation for acute ethanol effects.

Conclusion
We show that ethanol acutely induces late INa upstream of arrhythmogenic SR Ca2+-leak and delayed afterdepolarizations, dependent on NaV1.5 S571 phosphorylation, leading to atrial fibrillation in vivo. Importantly, these effects as well as AF in vivo can be prevented using the late INa inhibitor ranolazine. We suggest that this antianginal drug could be repurposed to prevent ethanol-induced AF.Late INa (Patch-Clamp)In vivo AF (programmed stimulation)
Cardiosphere derived cell secretome therapy after experimental myocardial infarction: effects of intracoronary administration on ventricular tachycardia inducibility and cardiac function
Authors: Baez Diaz C , Blanco Blazquez V , Sanchez Margallo F M , Torrescusa A , Pulido M , Lopez E , Arenal A , Crisostomo V 
Published: November 2023

Abstract

Background
Myocardial infarction (MI) carries high risk of sudden cardiac death due to the development of ventricular tachycardia (VT) which is caused by viable myocytes located within the infarct scar tissue [1]. Cardiosphere derived cell secretome (S-CDCs) has been demonstrated to possess antiarrhythmic properties when delivered transendocardially [2]. Further, S-CDCs has been proven to reduce scar size and increase viable myocardial mass in chronic MI [3].

Purpose
The objective of this study was to evaluate the effects of an intracoronary (IC) administration of S-CDCs on VT inducibility and cardiac function in a porcine MI model.

Methods
After obtaining the approval of the Institutional Animal Care and Use Committee, 14 Large White swine were subjected to closed chest MI induction carrying out balloon occlusion of the left anterior descending coronary artery (below the second diagonal branch) for 150 minutes. One month after MI creation, pigs received an IC administration of saline (CON; 5mL; n=7) or S-CDCs (S-CDCs; 9.16 mg of protein in 5mL of saline; n=7). VT inducibility and magnetic resonance (MR) studies were performed pre- and four months post-injection determining ejection fraction (EF), infarct size (IS) and indexed end diastolic and systolic volumes (EDVi, ESVi).

Results
Before injection VT was inducible in all cases and no differences were observed between groups in any MR-derived parameter (figure). IC infusion was successful in all swine. At four months VT inducibility study revealed lower inducibility rates in S-CDCs compared to CON (57% versus 100%; p=0.05). At this timepoint EF was higher in S-CDCs (35±10% versus 29±10%) although differences between groups were not statistically significant. Conversely, IS was significantly lower in S-CDCs (12±3% versus 16±2% (p=0.03)). Moreover, a trend towards lower ventricular volumes (EDVi: 83±18mL/m² versus 88±29mL/m² and ESVi: 56±20mL/m² versus 64±27mL/m²) was detected in this group.

Conclusions
The IC administration of S-CDCs suggests a potential reduction on post-MI VT development as well as a beneficial effect on cardiac function. This therapy seems to reduce IS in this porcine MI model.MR derived parameters
Chd4 and Zbtb7b cooperate to inhibit Cardiac Arrhythmia by repressing Cornifin-A expression
Authors: El Abdellaoui Soussi F A S , Novillo A N , Redondo J M R , Gomez-Del Arco P 
Published: November 2023

Abstract
Cardiac arrhythmias are life-threatening pathologies worldwide, but their etiology and development are still under debate. We have recently described that the Chd4/NuRD chromatin-remodeling complex is one of the epigenetic regulators involved in the maintenance of cardiac muscle identity. Indeed, conditional cardiomyocyte deletion of Chd4 (Chd4cKO) in mice induces arrhythmias, in part due to aberrant expression of the skeletal muscle sarcomeric gene program in differentiating and terminally differentiated cardiomyocytes (Gomez-del Arco et al. 2016 and El Abdellaoui-Soussi, 2022). In addition, we also discovered that numerous cardiac conduction system (CCS)-specific genes such as Hcn4, Cntn2, Cx43, Cx40, among others, were deregulated in these mutant mice. To better characterize the triggers of arrhythmogenesis in these Chd4cKO mice, we performed an in silico search for transcription factors (TFs) interacting with Chd4 in the heart and found that Zbtb7b could be one of these TFs. We therefore generated cKO mice for both genes and found that the arrhythmias appearing in the Chd4/Zbtb7b double KO (dKO) were much more severe than in the Chd4cKO and, therefore, dKO animals succumbed to sudden death faster than their Chd4cKO counterparts. In RNA-Seq experiments, we found that cornifin-A was synergistically overexpressed in dKO vs Chd4cKO and that the aberrant expression of this protein increased stiffness and apoptosis of cardiomyocytes, which could explain the observed exacerbated phenotype. Moreover, this overexpression was, at least in part, due to the concomitant downregulation of the micro-RNA miR-150-5p. Thus, our data provide paramount mechanistic evidence for a direct control of heart homeostasis in adult hearts by the Chd4/NuRD chromatin-remodeling complex in cooperation with the transcription factor Zbtb7b.
Vitronectin promotes TTR deposition and mitochondrial damage in ATTR-CA mice
Authors: Fan Y Z , Qiu Z P , Wang Z Y , Yang W B , Huang F Y , Chen Y J , Yang K , Jin W 
Published: November 2023

Abstract

Background
Transthyretin cardiac amyloidosis (ATTR-CA) is an increasingly recognized disorder that leads to heart failure and cardiovascular death. However, the pathogenesis of ATTR-CA is still poorly understood. Vitronectin (VTN), a common component of the extracellular matrix, has been reported to be associate with amyloidosis. However, the role of VTN in TTR deposition has not been clarified.

Purpose
Here we aimed to elucidate the TTR deposition mechanism in ATTR-CA and test therapeutic interventions using a gene-edited ATTR-CA mice model.

Methods
We used CRISPR/Cas9-mediated genome engineering to create humanized wild-type TTR knock-in mice (hTTRWT). Cardiac function was examined by echocardiography and pressure-volume analysis. VTN expression was assessed by immunofluorescence and western blotting. Interactions among VTN and TTR are analyzed with in vitro pull-down and co-immunoprecipitation (Co-IP) assays. Recombinant TTR protein was added in the culture of VTN overexpressed mice primary cardiomyocytes (CMs) to simulate the TTR deposition process in vitro. Mitochondrial function was determined by the Seahorse assay and mitochondrial ultrastructure was evaluated with the transmission electron microscope.Additionally, we assessed the mitochondrial damage with mitoSOX staining.

Results
In the hTTRWT group, pressure-volume analysis and echocardiography revealed significant diastolic dysfunction and increased left ventricle chamber stiffness at 52 weeks. Compared to WT group, the hTTRWT group showed a dramatic elevation of VTN in hearts. Co-IP and pull-down assays confirmed a direct interaction between VTN and TTR. In cultured CMs exposed to recombinant TTR protein, VTN overexpression promotes the deposition of TTR. Damaged mitochondrial ultrastructure, elevated oxidative stress and decreased mitochondrial numbers were found. In accordance with observed mitochondrial abnormalities, seahorse experiments demonstrated impaired mitochondrial respiration capacity.

Conclusion
These results suggest that the VTN contributes to ATTR-related pathological and cardiac function changes and mitochondrial dysfunction as a contributor of disease progression from ATTR-CA to heart failure.
Mechanomics study of cardiomyocytes with filamin c truncations
Authors: Lazzarino M , Chen S N , Gao S , Zanetti M , Taylor M R G , Mestroni L , Sbaizero O 
Published: November 2023

Abstract

Background
Filamin C (FLNC) is expressed in cardiomyocytes, where it binds to actin and localizes to Z-discs, sarcolemma, and intercalated discs. Although FLNC truncation variants (FLNCtv) are an established cause of arrhythmias and heart failure (arrhythmogenic cardiomyopathy), the underlying mechanisms, in particular changes in mechanical properties of cardiomyocytes, are mostly unknown.

Purpose
In this study, we applied a biophysical approach to investigate the interaction between altered mechanical properties and biological response in human induced pluripotent stem cells–derived cardiomyocytes (hiPSC-CMs) carrying FLNCtv.

Methods
CRISPR/Cas9 genome-edited FLNC-/- hiPSC-CMs, a homozygous condition that is lethal in animal models, and FLNC+/- hiPSC-CMs, recapitulating the heterozygous human disease, were analyzed. Wild-type FLNC hiPSC-CMs were used as controls. Atomic Force microscopy (AFM) was used to perform single-cell force spectroscopy (SCFS) microindentation, to evaluate passive and dynamic mechanical properties. From the loading curves, two cell Young’s Moduli were calculated: E1, related to the compression of the plasma membrane and actin cortex, and E2, including the rest of the inner cell layers (cytoskeleton and nucleus). Cell adhesion was assessed using the retraction curve of the SCFS. Data were processed in terms of adhesion force (the highest value of the force exerted by the cell-surface contact to the cantilever during retraction) and work of adhesion (integrating the area under the retraction curve). Finally, FLNC-/- hiPSC-CMs were incubated with 1 µM Crenolanib (a PDGFRA signaling inhibitor) for 3 days, and the microindentation was performed again using DMSO-only-treated FLNC-/- cells as controls.

Results
The AFM indentation curve for the cells analyzed showed significant differences. Both elastic contributions (E1 and E2) show that wild-type FLNC iPSC-CMs are stiffer than both mutant FLNC+/- and FLNC-/- iPSC-CMs (see Figure upper panel). The adhesion showed the same trend as the elasticity: mutant FLNC iPSC-CMs showed a progressive decrease of work of adhesion as well as max adhesion force from the FLNC+/- to the FLNC-/- models. Rescue of the latter with Crenolanib showed to moderately increase their stiffness. Moreover, a qualitative analysis of the beating traces showed that FLNC+/- but mostly FLNC-/- display "irregular" small peaks, resembling those of delayed after depolarizations (see Figure lower panel).

Conclusions
We found that FLNCtv causes a decrease in cell stiffness which declines progressively from the heterozygous status, which is associated with FLNC haploinsufficiency, to the homozygous status, which lacks FLNC. This indicates a progressive softening of the cardiomyocytes, suggesting a damaged cytoskeleton. Crenolanib rescue suggests that the inhibition of PDGFRA signaling could partially restore such damage (see Figure upper panel - right corner).
The impact of postmenopausal osteoporosis on aortic valve stenosis in an animal model
Authors: Billig H , Schmitt J , Singer L , Schildberg F , Goody P R , Vogel W , Perner S , Nickenig G , Zimmer S 
Published: November 2023

Abstract

Background
Aortic valve stenosis (AVS) is the most prevalent heart valve disease worldwide and mainly affects the elderly. In observational clinical studies, postmenopausal osteoporosis, which affects 30 % of all women, is associated with increased aortic valve calcification and stenosis. However, there are no pathomechanistic investigations that link these diseases.
In this study, we analyzed the impact of postmenopausal osteoporosis in ovariectomized C57BL6/J mice on the occurrence and progression of wire injury-induced aortic valve stenosis.

Methods
To induce postmenopausal osteoporosis, we performed bilateral ovariectomy (OVX) or sham operation in C57BL6/J mice. Successful OVX was confirmed by measuring the uterine weight. To distinguish the impact of estrogen deprivation from osteoporosis effects, 100 µg of the bisphosphonate zoledronic acid (ZA) or vehicle were applied i.p. weekly. Bone density was assessed through histological and µCT-analysis of the distal femur.
14 days after ovariectomy, AVS (or sham-procedure) was induced through a standardized, echocardiography-controlled injury of the aortic valve with a spring wire. Primary endpoint was the increase of peak velocity 2, 4 and 6 weeks after AVS-procedure. 8 weeks after OVX, mice were sacrificed and organs were harvested for further analysis (Fig. 1A).

Results
Bone mineral density and relative bone volume was significantly reduced 8 weeks after OVX. ZA led to a significant increase in bone mineral density, trabecular thickness and relative bone volume in comparison to the sham/vehicle and OVX/vehicle-groups (Fig. 1B-C).
AVS was successfully induced, as shown by a significant increase in peak velocity (PV; Fig. 2A-B) 2, 4 and 6 weeks after wire injury.
PV and mean pressure gradient (MPG) showed no difference between OVX- or Sham-operated mice (Fig. 2A). ZA did not significantly affect PV or MPG after AVS-procedure (Fig. 2B). Histological analysis revealed significantly greater cusp area in mice with AVS, but no difference for OVX- or ZA-groups (Fig. 2C). Picrosirius red staining showed a significantly decreased relative and absolute collagen content in aortic valves derived from mice with AVS, but no difference between OVX- or ZA-groups was detectable. Immature/degraded collagen was increased in mice with AVS.

Conclusion
Estrogen depletion and reduction in bone mineral density did affect AVS development in C57BL6/J mice. Application of ZA was effective in preventing bone loss, but did not change AVS-severity.
Further histological analysis of the aortic valves could reveal potential differences in cardiovascular osteoclast- and immune cell-infiltration.Figure 1Figure 2
Optimal pixel signal intensity threshold for the assessment of endocardial left-ventricular scar by 3D dark blood MRI compared to bipolar voltage electro-anatomical mapping
Authors: Kaya Y S , Stoks J , Gommers S , Holtackers R J , Duijsings R , Vernooy K , Volders P , Ter Bekke R 
Published: November 2023

Abstract

Background
Late gadolinium enhancement (LGE) MRI is considered the standard for noninvasive assessment of 3D scar architecture. Intraprocedural integration of 3D scar models improve the outcome of catheter ablation for ventricular tachycardia (VT). A pixel signal intensity (PSI) cut-off of 40 to 60% has been widely used for conventional bright-blood LGE MRI. Novel 3D MRI acquisitions with dark-blood (DB) nulling with higher spatial resolution and superior detection of (subendocardial) scar patterns are increasingly available, but the optimal pixel signal intensity (PSI) value remains unknown.

Purpose
To compare the accuracy of the 3D DB MRI-derived endocardial scar reconstructions at three different PSI cut-offs with endocardial electro-anatomical contact mapping in patients with scar-related VT.

Methods
Preprocedural 3D DB LGE MRIs were retrospectively compared to high-density endocardial left-ventricular (LV) bipolar voltage mapping (cut-off 0.5-1.5mV) obtained during endocardial mapping at sinus rhythm using the ADAS3D software. The LV scar models were aligned using the mitral valve, left ventricular apex and aorta cusps. Points with a Euclidean node-to-node distance of ≥10 mm were excluded. Variable upper PSI thresholds were set at 50%, 60% and 70%; the lower threshold at two-thirds of the upper limit. The 10% LV layer from the 3D MRI was used. The pairs of points were checked for agreement for scar or healthy (%). The Pearson correlation was used to analyze the agreement between core scar, border zone and healthy tissue area (in %) at three thresholds.

Results
Ten patients (90% male, mean age 65±11 year, 8 ischemic/2 nonischemic, LV ejection fraction 41±6%) were analyzed. A mean of 2024 (range 385-6810) pairs were analyzed per patient at three PSI thresholds. A correct correlation for scar or healthy was present in 67%, 69% and 69% for the upper PSI thresholds of 50%, 60% and 70% respectively. The optimal match was obtained for an upper PSI cutoff value of 70%, for healthy (r2=0.57; P=0.01), border zone (r2=0.73; P=0.01), 50% for core (r2=0.09; P=0.39). Using a 60% PSI cutoff the scar core % increased significantly compared to the 70% cutoff (12.8 ±13.8 versus 4.9±7.3, P=0.001).

Conclusion
The optimal depiction of the boundary between healthy and border zone scar by 3D DB MRI is best depicted at an upper PSI threshold of 70%.
The role of cellular senescence in aortic dissection
Authors: Nakao E , Aoki H , Hashimoto Y , Majima R , Hori-Hayashi M , Ito S , Ohno-Urabe S , Furusho A , Nishida N , Hirakata S , Fukumoto Y 
Published: November 2023

Abstract

Background
Aortic dissection (AD) is a catastrophic disease with high mortality. Survived patients frequently suffer from serious complications due to progressive destruction of the aortic walls. Recently we have reported that cell proliferation precedes the inflammatory response which is important in AD development and progression. Since cell proliferation promotes cellular senescence that can induce inflammatory response through SASP (senescence-associated secretary phenotype), we hypothesized that cellular senescence plays a critical role in AD pathogenesis.

Purpose
To investigate if cellular senescence contributes to AD pathogenesis in a mouse AD model.

Methods and Results
A mouse AD model was created by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII), where AD occurs to most of the mice in 14 days. BAPN+AngII challenge resulted in the appearance of senescent cells in the aortic walls before AD onset, which persisted for 14 days. Senescent cells, as demonstrated by the expression of senescence-associated beta-galactosidase, were evident in multiple types including endothelial cells, medial smooth muscle cells, adventitial macrophages and fibroblasts. Rapamycin, an inhibitor of mTOR pathway, suppressed the cell proliferation, the cellular senescence, and the development and progression of AD. To examine the role of cellular senescence in AD pathogenesis, ABT263, which is a senolytic drug that eliminates senescent cells, was administered orally to AD model mice. ABT263 treatment reduced the expression of the senescence markers. In the ABT263-treated group, the AD mortality was significantly decreased compared to that in vehicle-treated group (35% vs 67%, P &lt; 0.05 by log-rank test). The severity of AD, as assessed by the lesion length, was also attenuated in ABT263 group (24.6 ± 1.8 mm vs 33.2 ± 3.1 mm, P &lt; 0.05). Transcriptome analysis revealed that ABT263 treatment suppressed the aortic immune and inflammatory response induced by BAPN+AngII. Quantitative RT-PCR of aortic tissue confirmed that ABT263 treatment prevented the induction of p21, interleukin-6, several chemokines and M1 macrophage marker (CD80). ABT263 treatment suppressed CD80 expression also in cultured macrophages.

Conclusions
These results indicated that cell proliferation and senescence via mTOR pathway are critically involved in AD pathogenesis. Cellular senescence contributes to the inflammatory response including M1 differentiation of macrophages, and to the severity and the mortality in AD. Cellular senescence could be a new therapeutic target for AD.
Gamma-delta T cells: their atherogenic actions and therapeutic potential in atherosclerosis
Authors: Kyaw T , Kanellakis P , Brassington K , Cao A , Toh B H , Bobik A 
Published: November 2023

Abstract

Introduction
Atherosclerosis, a chronic inflammatory disease of the arteries, is a major contributor to ischemic attacks in the heart. Immune cells are studied in atherosclerosis and recognized as important players in plaque instability; however, multipotent γδ-T cells are rarely studied. Here, we aim to investigate their role in chronic arterial inflammation and the therapeutic potential of targeting them in preventing plaque instability.

Methods
Depletion and repletion strategies were adopted to examine the critical role of bone marrow derived γδ-T cells in atherosclerosis. Their direct atherogenicity mediated by interferon- γ (IFN-γ) and perforin (pfp) was investigated in mixed chimeric mice with specific protein deficiency restricted to bone marrow derived γδ-T cells. Anti -mouse TCR γ/δ antibody was employed to examine the master regulatory role of γδ-T cells in plaque stability. Mice with established atherosclerosis were treated with small molecule CXCR3-antagonist, AMG487 to retard γδ-T cell-modulated plaque instability.

Results
We confirmed that bone marrow derived γδ-T cells promote atherosclerosis and plaque stability. They directly contribute to lesion inflammation and cell death via IFN-γ and pfp leading to expanding vulnerable plaques. In addition, γδ-T cells express innate activating receptors, NKG2D and DNAM-1, for their activation in lesion and activated γδ-T cells recruited proinflammatory and cytotoxic immune cells via chemoattractants Rantes and MIP-1α, suggesting their pivotal roles in lesion progression. AMG487 treatment inhibited γδ-T cells and other immune cells and reduced atherosclerotic lesions with stable plaque characteristics - less cytotoxicity, more vascular smooth cells and thicker caps.

Conclusion
We have shown that bone marrow-derived CD27-positive γδ-T cells are most important immune cells in atherosclerosis. They contribute lesion cytotoxicity and inflammation by direct effector functions and influencing other atherogenic cells, and targeting them with AMG487 may be beneficial to reduce generation of vulnerable plaques and subsequent rupture so that it can significantly reduce MI.