bluuebunny/crossref_metadata_2025_split huggingface dataset:
Massive expansion of functional human iPSC-derived cardiomyocytes by concomitant glycogen synthase kinase-3 beta inhibition and removal of cell-cell contact
Authors: Buikema J W , Lee S , Maas R G J , Van Der Velden J , Sluijter J P G , Wu S M 
Published: November 2023

Abstract

Background
Adult mammalian heart has limited capacity for regeneration. Cardiac injuries such as myocardial infarction lead to significant cardiomyocyte (CM) loss and subsequent heart failure with significant morbidity and mortality. Cell-based therapeutic approaches such as injection of stem cell-derived cells or transplantation of engineered cardiac tissue patches have shown promise to re-muscularize the damaged myocardium and enhance cardiac functions.
Rationale: Modulating signaling pathways including Wnt and Hippo can induce cardiomyocyte proliferation in vivo. Applying these signaling modulators to human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in vitro can expand CMs modestly (&lt; 5-fold).

Results
Here, we demonstrate massive expansion of hiPSC-CMs in vitro (i.e. 100 to 250-fold) by glycogen synthase kinase-3β (GSK-3β) inhibition using CHIR99021 and concurrent removal of cell-cell contact. We show GSK-3β inhibition suppresses CM maturation while contact removal prevents CMs from cell cycle exit. Remarkably, contact removal enabled 10- to 25-times greater expansion beyond GSK-3β inhibition alone. Mechanistically, persistent CM proliferation required both LEF/TCF activity and AKT phosphorylation but was independent from Yes associated protein (YAP) signaling. Engineered heart tissues from expanded hiPSC-CMs showed comparable contractility to those from unexpanded hiPSC-CMs, demonstrating uncompromised cellular functionality after expansion.

Conclusion
In summary, we uncovered a molecular interplay that enables massive hiPSC-CMs expansion for large-scale drug screening and tissue engineering applications.
Stromal cell models of arrhythmogenic cardiomyopathy
Authors: Iengo L , Maione A S , Meraviglia V , Rabino M , Chiesa M , Catto V , Tondo C , Pompilio G , Bellin M , Sommariva E 
Published: November 2023

Abstract

Background
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease mainly associated with mutations in genes encoding cardiac desmosomes, most frequently Plakophilin-2 (PKP2). Primary cardiac mesenchymal stromal cells (CMSCs) were shown to contribute to the aberrant ACM cardiac remodeling based on their ability to differentiate into adipocytes and myofibroblasts, thus representing a useful in vitro model for the disease. The limitations associated with access to biopsies and finite passages in culture have been overcome by the advancement of stem cell technology, especially human induced pluripotent stem cells (hiPSCs) and their ability to differentiate towards cardiac stromal population. Specifically, CMSCs from hiPSCs provide a virtually unlimited cell sources that are genetically identical to patient cells of origin.

Purpose
The study compares hiPSC-derived stromal cells (hiPSC-D) and primary stromal cells (PRs), to explore the feasibility to use iPSC-D as an alternative in vitro model to study ACM.

Methods
PRs were isolated from ACM patients and healthy donors (HC). hiPSCs from a PKP2 mutated ACM patient (c.2013delC) and a sex/aged matched HC were used to produce iPSC-D. Flow cytometry analysis and specific differentiation induction (osteogenic, chondrogenic, adipogenic and pro-fibrotic) were performed to confirm mesenchymal lineage and multipotency. qRT-PCR and western blot analysis were performed to evaluate the expression of desmosomes, both gene and protein levels. Illumina transcriptomic profiling of both PRs and iPSC-D were compared and enriched pathways were identified by GSEA.

Results
Both PR and iPSC-D cells expressed mesenchymal surface markers and were able to differentiate towards osteogenic, chondrogenic, adipogenic and myofibroblast lineages. Desmosomal genes and proteins were expressed by both populations, showing a general trend toward lower expression of desmosomal markers in ACM compared to HC cells. Overall, higher expression of desmosomes was observed in iPSC-D stromal cells compared to their primary counterparts, independently on the genotype. As occurs for PRs, ACM iPSC-D exhibited an increased propensity to accumulate lipid droplets and collagen compared to HC cells. Moreover, both cell populations shared a highly similar transcriptomic profile, showing a significant linear correlation (R=0.85). Interestingly, PRs were enriched for genes associated with the immune response and differentiation processes, hinting to the hypothesis that an inflammatory stimulus received from the cardiac tissue might activate the innate immunity and drive the cell differentiation fates in the PRs.

Conclusion(s)
Both PR and iPSC-D cardiac stromal cells obtained from ACM patients can be used to model the disease, where the choice for the most suitable cell populations can be determined by the experimental strategy and/or the availability of human primary material.
Human epicardial adipose tissue-secreted miR-92a-3p regulates myocardial redox state via paracrine signalling: implications for cardiovascular clinical outcomes
Authors: Badi I , Carena M C , Polkinghorne M , Akoumianakis I , Psarros C , Kotanidis C P , Akawi N , Antonopoulos A S , Sayeed R , Krasopoulos G , Srivastava V , Douglas G , Channon K M , Casadei B , Antoniades C 
Published: November 2023

Abstract

Background
Visceral obesity is directly linked to increased cardiovascular risk, including heart failure.

Purpose
We explored the ability of human epicardial adipose tissue (EAT)-derived microRNAs (miRNAs) to regulate the myocardial redox state and clinical outcomes.

Methods
The 5 study arms included 466 patients undergoing cardiac surgery to perform: 1) the discovery phase in which we screened for 351 miRNAs expressed and released from human EAT; 2) correlation analyses between EAT microRNAs and myocardial expression of their targets or myocardial superoxide production in paired EAT/atrial biopsies; 3) genome-wide association screening for miR-92a-3p expression in EAT to test causality/directionality; 4) ex vivo experiments to investigate the underlying mechanisms that were also studied in vitro and in vivo; 5) an 8-year follow-up study to test the prognostic value of the discovered miRNA. Superoxide (O2.-) generation was measured by lucigenin chemiluminescence with NADPH 100μM stimulation as indicator of NADPH-oxidases activity. Vas2870 400 μM (a specific pan-NADPH oxidase inhibitor) was used to obtain the Vas2870-inhibitable O2.- signal which constitutes a more specific index of NADPH oxidase activity. Activation of Rac1, a key NADPH-oxidases subunit, was evaluated by a commercially available kit. Differentiated H9c2 cells were used as an in vitro model of cardiomyocytes. Doxycycline-inducible Wnt5a-overexpressing mice were used for in vivo experiments.

Results
The EAT secretome profiling on study 1 patients led us to identify 3 microRNAs both expressed and released by EAT whose levels in EAT correlated with oxidative stress in human myocardium. Among these miRNAs only miR-92a-3p reduced NADPH-oxidase-derived superoxide (O2.-) in cardiomyocytes (A). A genetic screening identified 7 SNPs that were associated with high miR-92a-3p levels in EAT (EAT-miR-92a-3p SNPs) and were related to lower myocardial superoxide production (B). miR-92a-3p decreased both activation of Rac1 (not shown) and Wnt5a protein levels in vitro (C). Patients with high EAT miR-92a-3p levels had lower WNT5A levels in the myocardium (not shown). Ex vivo, in vivo and in vitro experiments showed opposite effects of Wnt5a on Rac1-mediated NADPH-oxidases activity (D and not shown). Finally, we found an association of miR-92a-3p levels in EAT with lower relative risk of adverse cardiovascular events (E).

Conclusions
EAT-derived miRNAs exert paracrine effects on the human heart. Indeed miR-92a-3p suppresses the Wnt5a/Rac1/NADPH oxidase axis and improves myocardial redox state. EAT-derived miR-92a-3p is related with improved clinical outcomes and is a rational therapeutic target for the prevention and treatment of obesity-related heart disease.
Analytics of long-term premature ventricular complexes using an insertable cardiac monitor
Authors: Chu A F , Rajagopal G , Sarkar S , Landman S , Koehler J , Pothineni N V K 
Published: November 2023

Abstract

Background
Premature ventricular complexes (PVC) are associated with the development of cardiomyopathy, heart failure and pro-arrhythmia. PVC detection using insertable cardiac monitor (ICM) signal processing has recently been introduced. An ICM device capable of monitoring PVC burden over a longer period can be a useful tool for evaluating long-term PVC burden trends.

Purpose
This study evaluated the various long-term PVC burden trends from patients with implanted ICM capable of continuous PVC burden monitoring.

Methods
The ICM implemented PVC detection algorithm uses various combinations of long-short-long RR interval sequence and similarity and differences in R-wave morphology for three consecutive beats to detect single PVC events. For this study, long-term daily PVC burden trends from real-world patients implanted with ICM which has the capability of PVC detection using the implemented device PVC algorithm were analyzed from the de-identified Electronic Health Record (EHR) database linked with ICM device data warehouse. Examples of long-term PVC burden trends showing dynamic burden changes were evaluated and other PVC burden metrics such as maximum PVC burden, mean, and median PVC burden are analyzed from these ICM patients.

Results
PVC burden data from 1919 unique patients with implanted ICM were analyzed. 1814 patients with at least 90 days of available PVC burden were chosen for evaluation. There were 396,033 days with daily PVC burden data points that were evaluated with an average of 218 (SD=72) days with available PVC burden data per patient. The mean PVC burden which was defined as total PVC count divided by total days with ICM PVC detection enabled was 0.8 (SD=2.3) and median PVC burden was 0.02 (IQR 0-0.6). There were 6945 days (1.8%) with PVC burden values ≥10% in 168 unique patients (9.3%). 786 patients (43%) had a maximum daily PVC burden of ≤5% and 155 patients (9%) had maximum daily PVC burden between 6-10%. 107 patients (6%) had a maximum daily PVC burden between 11-20% and 40 patients (2%) had a maximum daily PVC burden &gt;20%. The clinical history comparison of 1814 ICM patients based on a cutoff of a maximum daily PVC burden of 10% is shown in figure 1. Figure 2 shows examples of long-term daily PVC burden(%) trends from four different patients from this dataset showing dynamic PVC burden variabilities that only long-term monitoring of PVCs could detect.

Conclusion
PVC burden monitoring performed utilizing a unique PVC detection algorithm can provide longitudinal and long-term dynamic PVC burden trends in patients implanted with ICM. Dynamic changes in PVC burden may be associated with cardiac pro-arrhythmia or hospitalizations and requires further investigation.
Performance comparisons between two artificial intelligence based premature ventricular complex detection models using insertable cardiac monitor
Authors: Pothineni N V K , Rajagopal G , Sarkar S , Chu A F 
Published: November 2023

Abstract

Background
Premature ventricular complex (PVC) detection using computationally simple techniques has been recently introduced in insertable cardiac monitors (ICMs). An ICM device capable of monitoring PVC burden over a longer period can be a useful tool for evaluating temporal dynamics of PVC burden leading to appropriate and timely clinical interventions in patients with high PVC burden.

Objective
The study evaluated the performances of two artificial intelligence (AI) based PVC detection models to improve PVC detection accuracy in ICMs.

Methods
We developed and evaluated two deep learning convolution neural network (CNN) based PVC detection models which were trained and validated on ICM ECG data. The models were developed and validated using ECG strips stored by ICM implanted in real world patients and collected in the deidentified ICM device data warehouse. All ECG strips were manually annotated for PVCs beat-by-beat. For the first model, only the ICM ECG of three consecutive beats was provided as an input feature whereas for the second model, additional features including QRS morphology differences, RR interval differences, QRS amplitude and slope differences between adjacent beats were extracted and provided as input. The trained AI models were tested on a validation dataset and performance metrics including accuracy, sensitivity and specificity metrics were computed and compared between both models.

Results
The CNN ResNet-18 models with different input features were trained and validated on a dataset of over 90 patient activated ICM ECG episodes which provided a total of 14,354 beats with over 2,200 PVC beats. This dataset provided PVC beats with different morphologies including monomorphic, polymorphic, bigeminy and trigeminy PVCs. The validation dataset consisted of over 4,300 beats including 664 true PVC beats with various morphologies. On the validation dataset, the first model with only ECG as input obtained an accuracy, sensitivity and specificity of 98%, 92% and 99.1% respectively. Whereas for the second model with ECG plus additional features as input, an accuracy, sensitivity and specificity of 98.9%, 97.3% and 99.2% were obtained respectively (Figure 1). Error analysis of both the AI models revealed that the main reason for misidentifying PVC beats was due to the presence of noise around the QRS complex or the T-wave of the beat in the ECG.

Conclusion
Detection of PVCs utilizing a novel AI algorithm is both feasible and capable of exceeding sensitivity and specificity performance metrics of non-AI based algorithms and AI models with manually extracted ECG features provide better performance for targeted PVC detection in ICMs.
EVs derived from physiologically loaded myocardial slices affect remodelling of overloaded myocardial slices
Authors: Nicastro L , Lal A , Kholia S , Chokron D , Downing B , Emanueli C , Terracciano C 
Published: November 2023

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 &lt; 0.05), higher blood vessel density (P &lt; 0.0001) and lower apoptosis (P&lt;0.01) compared to overloaded slices. Application of physiological EVs on overloaded slices restored their contractility (P&lt;0.05), attenuated apoptosis by reducing protein PARP-1 expression (P&lt;0.05) and reduced blood vessels density loss (P&lt; 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.
RTN3 interacted with FABP5 and promoted lipid droplet biogenesis in cardiomyocytes
Authors: Guo D , Zhang M M , Qi B C , Peng T W , Liu M C , Fu F E N G , Wang Y I N G , Hu L A N G , Li Y A N 
Published: November 2023

Abstract

Background
Lipid droplet (LD) accumulation is a notable feature of obesity-induced cardiomyopathy; however, detailed processes governing cardiac LD content remains poorly understood. Reticulon 3 (RTN3), a tubular endoplasmic reticulum (ER) localized protein, was recently identified as a key modulator of lipid metabolism in adipocytes. But its role in cardiac lipid metabolism and the specific mechanism of RTN3 regulating lipid content are currently unknown.

Purpose
To investigate the role of RTN3 in cardiac LD accumulation and the mechanism by which RTN3 affects LD metabolism.

Methods
We labelled LD, free fatty acids (FFA), and nucleus in cardiomyocytes with fluorescent markers and upregulated/downregulated RTN3 expression with adenovirus. The effect of RTN3 on cardiac LD content and biogenesis was detected with confocal microscopy. Then we investigated the interaction partner of RTN3 with co-immunoprecipitation (Co-IP), liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and immunofluorescence staining. The function of the complex which RTN3 formed with its interaction protein was then explored.

Results
RTN3 overexpression significantly increased LD content in cardiomyocytes, which phenocopied the effects of palmitate stress. In contrast, palmitate-induced LD accumulation was blocked by RTN3 knockdown. Tubular ER, where RTN3 residents, is the primary organelle regulating LD biogenesis. Based on that, we hypothesized that the effect of RTN3 on LD content could be attributed to its direct effect on LD biogenesis in the ER. Further FFA tracing results demonstrated that RTN3 overexpression and palmitate could markedly increase FFA-LD colocalization, suggesting the LD biogenesis was activated, but this increase in colocalization was absent in cardiomyocytes infected with Ad sh-RTN3. Live cell imaging also revealed that upregulation of RTN3 significantly accelerated cardiac LD biogenesis and downregulation of RTN3 suppressed palmitate-induce LD biogenesis. Then we investigated the interaction partner of RTN3 and found that RTN3 formed a complex with fatty acids binding protein 5 (FABP5), which is an intracellular carrier for long-chain FFAs. Mechanistically, RTN3 directly bound with FABP5, which facilitated the directed transport of FFA to ER and thus promoted LD biogenesis. FABP5 knockdown blocked RTN3-mediated LD biogenesis. Moreover, we discovered that the 1st-194th amino acids of RTN3 was responsible for interacting with FABP5 and promoting LD biogenesis.

Conclusions
Our study reveals a novel mechanism contributing to LD biogenesis in cardiomyocytes. Based on our results, manipulating LD biogenesis by modulating RTN3 may be a potential strategy for treating LD accumulation in obese patients.RTN3 promoted lipid droplet biogenesisRTN3 formed a protein complex with FABP5
Clinical value of insertable loop recorder: single centre experience
Authors: Ahmed M , Morris J P , Bommireddi S M , Cotici A 
Published: November 2023

Abstract

Background
The aetiology of syncope can be challenging to undermine because of its sporadic nature. Implantable loop recorders (ILR) are recommended to be used early in undetermined syncope to establish a symptom – rhythm correlation if cardiac syncope is suspected. Real world diagnostic yield of ILR is not well established.

Purpose
To evaluate the diagnostic yield of ILR devices in patients with undetermined syncope.

Methods
This single centre, retrospective study, reviewed the electronic medical records of all patients, who underwent ILR insertion for syncope from January 2017 to June 2022. Abnormal rhythm strips on ILR were reviewed by a cardiac physiologist and cardiology consultant to determine its significance.
Primary outcome was to determine the total number of cardiac implantable electronic devices (CIEDs) inserted due to ILR findings. Secondary outcomes included (1) a baseline characteristics comparison between the group of patients who had an arrhythmia detected on ILR and patients who had detected no arrhythmia, and (2) the total number of clinical significant events (CSEs), defined as a symptomatic arrhythmia, an asymptomatic arrhythmia deemed clinically related to the patients’ history of syncope, and the absence of an arrhythmia when the patient experienced syncope. Complications of ILR insertion were recorded.
Given that normality was not assumed, a non-parametric analysis was utilised to compare baseline characteristics.

Results
A total of 215 patients were included in this study, of which 43 (20%) had a CIED inserted due to ILR findings. Baseline characteristics were similar between the groups except age (Table 1).
103 (47.9%) of the patients had a CSE (Figure 1). Symptomatic arrhythmias were the most common clinically significant events, out of which a sinus pause of greater than 6 seconds was most prevalent arrhythmia. There were no complications that required early explant of the ILR in this cohort.

Conclusion
ILR detected a clinically significant arrhythmia and the absence of an arrhythmia in 42.7% and 5.1% of patients with undetermined syncope, respectively. ILR use is a valuable diagnostic tool in this cohort of patients. Further studies looking at cost-effectiveness would be beneficial.Baseline characteristicsCSE and arrhythmias