bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeting microtubule dynamics improves cardiac sodium channel function in arrhythmogenic cardiomyopathy
Authors: Nasilli G , Lin X , Perez-Hernandez M , Zhang M , Rothenberg E , Delmar M , Casini S , Remme C A 
Published: November 2023

Abstract

Background
Pathophysiological conditions such as heart failure and cardiomyopathy are associated with alterations in microtubule (MT) dynamics (in particular increased MT detyrosination), which have detrimental effects on cardiac function. Since the MT network is also involved in trafficking of ion channels to the cell membrane, its remodeling may also affect sodium channel (Nav1.5) function. Indeed, sodium current (INa) is typically decreased in the setting of heart failure and (arrhythmogenic) cardiomyopathy.

Purpose
To investigate the impact of MT detyrosination on Nav1.5 and INa in a mouse model of arrhythmogenic cardiomyopathy (tamoxifen-activated cardiac-specific knockout of plakophilin-2 (PKP2cKO)).

Methods and Results
Freshly isolated cardiomyocytes (CMs) from PKP2cKO mice were incubated for 2-4 hours with either 10 µM parthenolide (PTL; a compound that decreases the fraction of detyrosinated MTs) or vehicle only (DMSO). Vehicle-treated CMs from PKP2cKO mice displayed significantly increased levels of detyrosinated tubulin as compared to wild type (WT), which was attenuated by PTL treatment. PTL significantly increased whole-cell INa without affecting gating properties in PKP2cKO CMs, while it did not affect INa in WT CMs. Macropatch measurements demonstrated that PTL increased INa at both the cell end (Intercalated disc, ID) and lateral membrane (LM) of PKP2cKO CMs. Accordingly, stochastic optical reconstruction microscopy (STORM), a super-resolution approach, revealed that PTL increased Nav1.5 cluster density at both ID and LM of PKP2cKO CMs.

Conclusions
Reducing MT detyrosination by PTL increases Nav1.5 cluster density and sodium current magnitude in a mouse model of arrhythmogenic cardiomyopathy. These findings identify restoration of MT dynamics as a potential novel anti-arrhythmic therapeutic in the setting of cardiac pathology.
Validation of mitochondrial function measurements in permeabilized myocardial tissue from porcine left ventricular specimens with ischemia/reperfusion
Authors: Eickelmann C , Lieder H R , Heusch G , Kleinbongard P 
Published: November 2023

Abstract

Background
Mitochondrial function is critical to myocardial ischemia/reperfusion injury and cardioprotection. The measurement of mitochondrial function in isolated mitochondria requires cardiac specimens of about 300 mg and is therefore only possible at the end of an animal experiment or during cardiosurgical interventions in humans. As an alternative, permeabilized myocardial tissue can be used for quantification of mitochondrial respiration in small myocardial specimens of about only 2-5 mg, which can be retrieved by sequential biopsies in animal experiments and during cardiac catheterization in humans. Whether or not mitochondrial dysfunction during ischemia/reperfusion is reflected to the same extent in saponin-permeabilized myocardial tissue specimens (PMT) and in isolated mitochondria is still unclear.

Purpose
We attempted to validate measurements of mitochondrial respiration from PMT by comparison to those from isolated mitochondria in left ventricular myocardium from anesthetized pigs undergoing coronary occlusion/reperfusion.

Methods
Göttingen open-chest, anesthetized minipigs (n=10) were subjected to 60 min distal left anterior descending artery occlusion and 180 min reperfusion. At the end of reperfusion, PMT and isolated mitochondria were prepared from remote and ischemic/reperfused myocardium. Baseline, adenosine diphosphate-stimulated complex I (without/with cytochrome c, to account for absence or presence of the outer mitochondrial membrane integrity) and complex IV respiration was measured at 37°C during magnetic stirring using a high-resolution respirometer. Mitochondrial respiration in PMT and isolated mitochondria was normalized to protein content and the content of the mitochondrial marker protein cytochrome c oxidase 4.

Results
Mitochondrial respiration measurements in PMT and isolated mitochondria correlated well (Figure 1A) and agreed well in Bland-Altman plot (Figure 1B). While baseline respiration in PMT was somewhat higher than that in isolated mitochondria (Figure 2A), mitochondrial dysfunction during ischemia/reperfusion was equally reflected in PMT and isolated mitochondria (Figure 2B & 2C). Complex IV respiration was not different between remote myocardium and ischemic/reperfused myocardium, independently of the preparation, indicating a comparable amount of viable mitochondria (Figure 2D).

Conclusion
Mitochondrial function measurements in PMT can substitute for that in isolated mitochondria to reflect their dysfunction in ischemia/reperfusion. Thus, mitoprotective strategies targeting ischemia/reperfusion injury in small tissue samples and also in human myocardial biopsies can be followed in PMT.Figure 1Figure 2
Melatonin attenuates an impairment of metabolic reprogramming in doxorubicin-induced cardiotoxicity: insights from metabolomics study in rats
Authors: Thonusin C , Nawara W , Arinno A , Khuanjing T , Prathumsup N , Ongnok B , Chattipakorn S C , Chattipakorn N 
Published: November 2023

Abstract

Background
Doxorubicin is an effective chemotherapeutic agent. Unfortunately, the clinical utilization of doxorubicin is limited due to cardiotoxicity. It was previously shown that doxorubicin caused the changes in glycolysis metabolome levels, fatty acid levels, and genes involving lipid metabolism in the heart. However, the pattern of metabolic reprogramming in doxorubicin-induced heart failure remains unknown. Moreover, the benefit of melatonin in attenuating doxorubicin-induced heart failure was previously revealed. Nonetheless, the potential benefits of melatonin on metabolic reprogramming in doxorubicin-induced heart failure has never been determined.

Purposes
Using liquid chromatography coupled with mass spectrometry-based targeted metabolomics, we identified the pattern of metabolic reprogramming in rats with doxorubicin-induced heart failure. In addition, the effects of melatonin on metabolic reprogramming in doxorubicin-induced heart failure were investigated.

Methods
Male Wistar rats (n=18) were divided into 3 groups (n=6/group) to receive either 1) normal saline solution as a vehicle, 2) 3 mg/kg/day of doxorubicin at days 0, 4, 8, 15, 22, and 29, and 3) 3 mg/kg/day of doxorubicin at days 0, 4, 8, 15, 22, and 29 plus 10 mg/kg/day of melatonin at days 0-29. At day 30, echocardiography and heart rate variability were done for an evaluation of cardiac function. The rats were then euthanized to collect ventricular cardiac tissues for metabolomics study.

Results
Comparing to vehicle-treated rats, the heart of rats treated with doxorubicin alone exhibited cardiac dysfunction, increased glucose and ketone body utilization, decreased fat utilization, decreased succinate oxidation, and decreased adenosine triphosphate (ATP) production. The co-treatment with melatonin effectively restored cardiac function, glucose and ketone body utilization, and ATP production in the heart. Interestingly, the co-treatment with melatonin also increased cardiac fatty acid oxidation, branched-chain amino acid catabolism, and anaplerosis (Figure).

Conclusions
Our findings highlighted the potential benefits of melatonin on cardiac metabolic reprogramming impaired by doxorubicin. These findings also suggested that melatonin could be considered as an adjunctive treatment for doxorubicin-induced heart failure in clinical settings.
Macrophage expressed CD36 promotes plaque vulnerability in atherosclerosis
Authors: Gissler M C , Mwinyella T , Morguet C , Heitlinger S , Li X , Horstmann H , Willecke F , Marchini T , Westermann D , Wolf D 
Published: November 2023

Abstract

Background
Atherosclerosis is characterised by a chronic lipid-driven inflammation that accounts for the majority of deaths worldwide. CD36 is an immunoregulatory scavenger receptor at the interface of lipid metabolism and inflammation that is critically involved in atherogenesis. However, due to the lack of cell-specific in vivo models the exact role of CD36 on macrophages in atherosclerosis remains unknown to date.

Purpose
Here we aimed to evaluate the role of macrophage expressed CD36 in atherogenesis.
Approach & Results: To screen for a potential role of macrophage expressed CD36 in atherosclerosis we assessed CD36 gene expression across different leukocyte populations in single-cell-RNA Sequencing (scRNAseq) data from atherosclerotic LDLR-/- mice. Here, we identified macrophages as the main CD36 expressing cell type. In line, CD36 protein expression in aortic cell suspensions from LDLR-/- mice was significantly higher in macrophages compared to B and T cells as assessed by flow cytometry. To assess the role of macrophage expressed CD36 in atherogenesis, we generated macrophage specific CD36 deficient mice on an atherosclerotic prone LDLR deficient (LDLR-/-) background. CD36fl/fl-CXC3R1Cre LDLR-/- mice (termed iMΦ-CD36) and CD36fl/fl-CXC3R1Wt LDLR-/- controls (termed CD36fl/fl) were injected with tamoxifen for 5 consecutive days and placed on a high cholesterol diet for 16 weeks to induce atherogenesis. At harvest the aortic root was obtained from whole heart, embedded in OCT, cut and stained with Oil Red O staining for histological analyses of atherosclerotic lesions. Macrophages were differentiated from isolated bone marrow cells for in vitro assessment of ROS production and oxLDL uptake. Notably, Macrophage-specific CD36 deficiency did not affect atherosclerotic lesion size but substantially reduced the necrotic core area indicating ameliorated plaque vulnerability. In vitro, macrophage CD36 deficiency ameliorated ROS production and facilitated oxLDL uptake. Further, macrophage-specific CD36 deficiency reduced circulating MCP-1 levels. To interrogate a potential role of CD36 in human atherosclerosis, human atherosclerotic plaques were studies by scRNAseq. Similar to our observations in mice, cellular CD36 expression was highest in human macrophages/monocytes. Further pathway analysis revealed that CD36-expressing macrophages exhibited a significantly more pro-inflammatory gene signature than CD36-negative macrophages. Down this line, CD36 expression was significantly higher in unstable carotid plaques compared to stable lesions indicating that CD36 expression correlates with plaque vulnerability in humans.

Conclusion
All in all, our data indicates a pro-inflammatory role of macrophage expressed CD36 in murine and human atherosclerosis. These findings suggest that targeting CD36 on macrophages may represent a potential target for anti-atherosclerotic therapy.
Inhibition of ADAM10-mediated CX3CL1 shedding promotes survival and cardiac function early after myocardial infarction
Authors: Klapproth E , Witt A , Klose P , Guan K , Lorenz K , Saftig P , Wagner M , El-Armouche A 
Published: November 2023

Abstract

Background and Purpose
The metalloprotease ADAM10 has been implicated in immune regulatory processes, is upregulated in response to specific heart pathologies e.g. ischemic heart failure, and elevated serum levels of the ADAM10 substrates CX3CL1 and CXCL16 have been reported following infarction. The causal role of ADAM10 in cardiovascular diseases, however, is not known yet. By using human tissue biopsies, a cardiomyocyte-specific ADAM10 knockout mouse model (ADAM10 KO), and pharmacological ADAM10 inhibition we here comprehensively characterize the role of ADAM10 in the heart and in cardiac disease.

Methods and Results
We show that ADAM10 protein levels are upregulated in patients with ischemic cardiomyopathy (2.5-fold) and ADAM10 mRNA expression correlates with expression of atrial (NPPA) and brain natriuretic peptide (NPPB) mRNA. Upon infarction, ADAM10 expression is specifically induced in cardiomyocytes, and cardiomyocyte-specific ADAM10 KO as well as pharmacological inhibition (GI254023X) for only three days significantly improves overall survival, reduces scar size, and preserves cardiac function. Mechanistically, flow cytometry and bulk RNA sequencing identify a ADAM10/CX3CL1 axis to control neutrophil bone marrow egress and heart tissue infiltration after infarction. Diminished neutrophil migration results in long-term reduction of IL-1β-driven inflammation. Using cell culture experiments with ADAM10/CX3CL1 knockdown cardiomyocytes, we show that ADAM10-mediated ectodomain shedding of CX3CL1 specifically regulates neutrophil but not macrophage chemotaxis revealing a novel conceptual insight into how acute infarction triggers chemotactic signaling via ectodomain shedding.

Conclusion
Pharmacological and genetic targeting of the membrane sheddase ADAM10 is highly efficient for improving post-infarction cardiac function and survival via abolished post-translational CX3CL1 processing, neutrophil infiltration and IL-1β-dependent inflammation. Thus, our data reveal a novel therapeutic concept, which may close a clinically relevant therapeutic gap early after myocardial infarction.
Cryo-X-ray phase contrast imaging enables whole biopsy imaging prior to multi-omic analysis
Authors: Li K Y C , Dejea H , Bonnin A , Treibel T , Budhram-Mahadeo V , Garcia-Canadilla P , Cook A C 
Published: November 2023

Abstract

Background
Analysis of myocardial biopsies using conventional two-dimensional (2D) histological techniques is limited in the detection of important three-dimensional (3D) structural features, such as disarray, due to sectioning and artefacts from dehydration or chemical processing. More advanced techniques such as light-sheet microscopy, micro-computed tomography or synchrotron radiation-based X-ray phase contrast imaging can provide non-destructive, 3D histological information at high resolution for formalin-fixed and/or paraffin-embedded (FFPE) biopsies. However, formalin fixation induces crosslinking of proteins which can impact quality and their subsequent analysis, for example, fragmentation of nucleic acids. A method for imaging 3D structure of myocardial biopsies in near-native state is needed which can then be followed by downstream multi-omic applications.

Purpose
To develop a technique called cryogenic X-ray phase contrast imaging (Cryo-X-PCI) to image snap-frozen myocardial biopsies at controlled low temperatures, followed by multi-omic analysis starting with analysis of DNA and RNA.

Methods
Myocardial biopsies (n=46) were obtained from C57BL/6 mice and snap-frozen in liquid nitrogen fresh or after 4% paraformaldehyde (PFA);10% formalin fixation. Pilot human aortic stenosis biopsies were also included (n=3, fresh). X-PCI was performed at -70°C using a cryojet, 20 keV beam energy and 0.65 µm detector pixel size (Figure 1). Datasets were reconstructed using Gridrec algorithm and Paganin phase retrieval. Morphologic analysis (myocardial disarray index, fractional anisotropy, helical angle, and intrusion angle) of biopsies was performed using a structure tensor-based approach via in-house MATLAB script. After imaging, DNA and RNA were extracted from murine biopsies followed by assessment of quantity and quality.

Results
Increased intercellular space between aggregates of myocytes was observed in all samples. This is consistent with reported findings in skeletal muscle using cryogenic conditions. Nonetheless, morphologic analysis of the biopsies proved possible (Figure 2). Optimal recovery of DNA and RNA was obtained from fresh frozen samples as compared to 4% PFA-fixed or 10% formalin-fixed samples.

Conclusions
This study demonstrates Cryo-X-PCI as a potential tool for analysing myocardial biopsies of heart muscle disease including morphologic analyses. Levels of DNA and RNA were not significantly affected indicating that downstream genomics, proteomics and transcriptomics analyses should be feasible.Setup for Cryo-X-PCI of frozen biopsiesMorphologic analysis of a biopsy
Mitochondrial heteroplasmy as a marker for premature coronary artery disease: analysis of the poly-C tract of the control region sequence
Authors: Gonzalez Urbistondo F , Aparicio-Gavilanes A , Gomez J , Alvarez-Velasco R , Pascual I , Avanzas P , Alen A , Vazquez-Coto M , Gonzalez-Fernandez M , Garcia-Largo C , Cuesta-Llavona E , Moris De La Tassa C , Eliecer C , Lorca R 
Published: November 2023

Abstract
Mitochondrial DNA (mtDNA) differs from the nuclear genome in many aspects: a maternal inheritance pattern, being more prone to acquire somatic novo mutations, accumulative with age; and the possible coexistence of different mtDNA alleles (heteroplasmy). Mitochondria are key cellular organelles responsible for energy production, involved in complex mechanisms, including atherosclerosis. In this scenario, we aimed to evaluate mtDNA variants that could be associated with premature cardiovascular disease. We evaluated 188 consecutive patients presenting with premature myocardial infarction with ST elevation (STEMI) confirmed by coronary angiogram. mtDNA polymorphisms and clinical data were evaluated and compared with 271 individuals from the same population (control group). Tobacco consumption (80.85% vs 21.21%, p&lt;0.01) and dyslipidemia (38.83% vs 28.41%, p=0.02) were significant more frequent among STEMI patients. Besides, C16223T mtDNA mutation and poly-C heteroplasmy were significantly more frequent among premature STEMI cases than in controls. The OR associated C16223T mtDNA mutation with an increased presence of cardiovascular risk factors. Our data suggest that mtDNA C16223T mutation and poly-C heteroplasmy may be associated with unstable atherosclerosis disease. Moreover, the presence of cardiovascular risk factors (CVRFs) was associated to C16223T mtDNA mutation, with a cumulative effect. Protective mitochondrial pathways are potential therapeutic targets. Thus, preventing exposure to the damaging mechanisms associated to CVRFs is of the utmost importancemtDNA sanger analysisBaseline characteristics.
Selective cardiac myosin inhibitors protect the heart following ischemia-reperfusion injury
Authors: Yusof L , Yellon D M , Davidson S M 
Published: November 2023

Abstract

Background/Introduction
Following an acute myocardial infarction, reperfusion of an occluded coronary artery is often accompanied by cardiomyocyte injury, leading to a worse long-term prognosis. Cardiomyocyte hypercontracture in the first few minutes of post-ischemic reperfusion (IR) is a critical determinant of reperfusion-induced cell death. Inhibition of hypercontracture is highly cardioprotective, but the therapies available are non-specific and unsuitable for clinical translation. Recently, cardiac myosin-targeted inhibitors (CMIs) of contraction, Mavacamten and Aficamten, have been developed to treat patients with hypertrophic cardiomyopathy. These CMIs are well tolerated and safe in clinical trials, however they have not been investigated in the setting of IR injury.

Purpose
To investigate whether these CMIs could be repurposed to reduce reperfusion-induced hypercontracture following IR, which in turn would limit infarct size.

Methods
Male Sprague Dawley rats underwent in-vivo myocardial infarction with 30 min ischemia followed by 120 min reperfusion. 15 min prior to reperfusion, Mavacamten or vehicle (10 % DMSO with 90 % corn oil) were administered intraperitoneally. In addition, in vitro experiments using primary adult rat cardiomyocytes (ARVC) were undertaken to confirm the ability of both CMIs to inhibit hypercontracture. Isolated ARVC were pre-treated with either Mavacamten or Aficamten for 30 min before incubating with carbonyl cyanide m-chlorophenylhydrazone (cCCP) to induce cell contracture.

Results
Mavacamten (2mg/kg) vs control significantly reduced regional infarct size (38.4 ± 4.6 % vs 60.3 ± 5 %, p &lt; 0.05, n= 7-8). Notably, treatment with both Mavacamten (10mM) and Aficamten (1mM) were also inhibited the ability of cCCP to induce ARVC contracture in vitro, with significant reduction in cell contracture (59.7 ± 10.1 % and 49.8 ± 18.5 %, respectively vs control, 99.1 ± 0.6 %, p &lt; 0.05, n= 7).

Conclusion
These findings provide additional information for further studies into the potential of these CMIs to reduce reperfusion-induced hypercontracture clinically.
A large, real-world cohort analysis of arrhythmia detections with insertable cardiac monitors
Authors: Saha S , Zhou J , Rosemas S C , Ramos V , Radtke A P , Majumder S , Sims J J , Sarkar S 
Published: November 2023

Abstract

Background
Insertable cardiac monitors (ICMs) provide long-term continuous monitoring for arrhythmia diagnosis and management for various clinical indications. However, little data exists on the real-world diagnostic yield of ICMs across indicated patient populations, including both expected and incidental arrhythmic findings. Validated artificial intelligence (AI) algorithms have been developed to identify true arrhythmia episodes while significantly reducing false positives, enabling the adjudication of ICM episodes for larger cohorts of patients.

Purpose
To characterize comprehensive true arrhythmia detection rates in a large real-world population with long-term ICM monitoring.

Methods
De-identified patients ≥18 years receiving a Reveal LINQ ICM between Oct 1, 2016 – Sept 30, 2020 with no prior cardiac implantable electronic devices and ≥1 year of follow-up in the CareLink monitoring database were identified (N=12,013). Patients were stratified by reason for ICM placement: N=9,841 who received ICM for diagnosis of suspected arrhythmias (40.8% unexplained syncope, 38.3% cryptogenic stroke, 9.7% palpitations, 9.7% suspected atrial fibrillation (AF), 1.6% ventricular tachycardia), and N=2,172 who received ICM for management of known AF. Device-detected ECGs during long-term follow-up were identified and processed through previously validated arrhythmia-specific AI algorithms designed to reduce false positive arrhythmia detections (each trained using ICM data from ≥25,000 adjudicated ECG episodes and validated on an independent set of ≥5,000 adjudicated ECGs).

Results
Mean (SD) and median follow-up were 24.6(12.7) and 24.5 months, respectively. In patients receiving ICM for Suspected Arrhythmia, 5,492 patients (55.8%) had ≥1 AI-adjudicated arrhythmia detected during follow-up, with 2,472 (45.0%) of these patients having ≥2 arrhythmia types detected (Table). Mean (SD) time to 1st arrhythmia detection was 7.7(9.1) months; time to 2nd arrhythmia type detected was 12.3(10.4) months. Among the 6,958 patients with longer-term ICM follow-up ≥2 years, 2,931 (42.1%) had no arrhythmias detected (i.e., arrhythmia rule-out occurred). In patients receiving ICM for AF Management, 1,737 patients (80.0%) had ≥1 arrhythmia detected, and notably 1,074 (61.8%) of these patients had ≥1 arrhythmia detected during follow-up that was not AF. Mean (SD) time to 1st arrhythmia detection was 5.3 (7.7) months; time to 2nd arrhythmia type detected was 10.4(9.9) months.

Conclusions
In a large real-world ICM population, &gt;50% of patients had AI-adjudicated arrhythmia detections during long-term follow-up, with a significant proportion receiving additional arrhythmia diagnoses beyond the initial type diagnosed or suspected. These results suggest that in indicated patients, long-term continuous monitoring with ICMs can enable diagnosis of a variety of cardiac arrhythmias that may have otherwise remained undetected.