Cardiac myocyte

Amir Askari
Na/K-ATPase (the sodium pump) was discovered in the 1950s as the plasma membrane enzyme that carries out the coupled active transports of Na+ and K+ across the membranes of nearly all eukaryotic cells. It was not until the 1990s when it was shown that besides pumping ions, Na/K-ATPase is also capable of stimulus-induced interactions with neighboring proteins that lead to activations of signal transduction pathways causing cell growth. This article is an attempt to review the progress of the research on these signaling functions of sodium pump during the past 2-3 decades...
November 2, 2019: Cell Calcium
Elnaz Pouranbarani, Rodrigo Weber Dos Santos, Anders Nygren
Mathematical models of cardiac cells have been established to broaden understanding of cardiac function. In the process of developing electrophysiological models for cardiac myocytes, precise parameter tuning is a crucial step. The membrane resistance (Rm) is an essential feature obtained from cardiac myocytes. This feature reflects intercellular coupling and affects important phenomena, such as conduction velocity, and early after-depolarizations, but it is often overlooked during the phase of parameter fitting...
2019: PloS One
Ammar Al-Chalabi, Leo M A Heunks, Zoltán Papp, Piero Pollesello
Levosimendan is a calcium sensitizer that promotes myocyte contractility through its calcium-dependent interaction with cardiac troponin C. Administered intravenously, it has been used for nearly 2 decades to treat acute and advanced heart failure and to support the heart function in various therapy settings characterized by low cardiac output. Effects of levosimendan on noncardiac muscle suggest a possible new application in the treatment of people with amyotrophic lateral sclerosis (ALS), a neuromuscular disorder characterized by progressive weakness, and eventual paralysis...
November 2019: Journal of Cardiovascular Pharmacology
Marine Cacheux, Benjamin Strauss, Nour Raad, Zeki Ilkan, Jun Hu, Ludovic Benard, Stefan Feske, Jean-Sebastien Hulot, Fadi G Akar
BACKGROUND: STIM1 (stromal interaction molecule 1) is a calcium (Ca2+ ) sensor that regulates cardiac hypertrophy by triggering store-operated Ca2+ entry. Because STIM1 binding to phospholamban increases sarcoplasmic reticulum Ca2+ load independent of store-operated Ca2+ entry, we hypothesized that it controls electrophysiological function and arrhythmias in the adult heart. METHODS: Inducible myocyte-restricted STIM1-KD (STIM1 knockdown) was achieved in adult mice using an αMHC (α-myosin heavy chain)-MerCreMer system...
November 2019: Circulation. Arrhythmia and Electrophysiology
Jia-Wan Wang, Zi-Yi Xue, An-Shi Wu
AIMS: The cardioprotective effects of preconditioning against ischemia-reperfusion (I/R) injury depend on the structural integrity of membrane caveolae and signaling through G protein-coupled receptors (GPCRs). However, the mechanisms underlying opioid preconditioning are not fully understood. Here, we examined whether caveolins transmitted opioid-GPCR signals to the mitochondria to mediate cardioprotection. MAIN METHODS: Mice were treated with pertussis toxin (PTX) or saline...
November 9, 2019: Life Sciences
Dalia Mohamed Amin
Copeptin is a precursor for arginine vasopressin which is usually elevated in acute stress and cardiac emergencies. Bisphenol A (BPA) is an ideal plasticizing factor used in manufacturing of plastics and epoxy resins. To evaluate the cardio toxicity of bisphenol A and to assess copeptin as a cardio toxic diagnostic and prognostic biomarker in Wistar rats. Sixty Wistar rats were classified into three groups: group I, naive group received regular diet and water; group II, vehicle group administered corn oil; and group III, each rat received BPA daily with (30 mg/kg/day S...
November 11, 2019: Environmental Science and Pollution Research International
Wei Huang, Qianhui Zhang, Hanping Qi, Pilong Shi, Chao Song, Yongsheng Liu, Hongli Sun
Increasing neuropeptide Y (NPY) has been shown to be a risk factor for cardiovascular diseases. However, its role and mechanism in myocardial infarction (MI) have not yet been fully understood. H9c2 cells and neonatal rat ventricular myocytes with loss of function of NPY and rats with global knockout were used in this study. MI model of rats was induced by the ligation of left coronary artery, and the extent of MI was analyzed through echocardiographic, pathological, and molecular analyses. Our data demonstrated that NPY expression was significantly increased in MI rats and hypoxia/hydrogen peroxide (H2 O2 )-treated cardiomyocytes...
2019: Frontiers in Pharmacology
Chiara Toni, Francesca Iannaccone, Piersilvio Chella, Fulvio Basolo, Angela Pucci
Herein we report an unusual case of sudden death occurring in a 65 year old woman during a minor oral surgery. The subject, who had a medically treated anxiety, had a history of two reversible left ventricle dysfunction episodes consistent with recurrent Takotsubo Syndrome that had occurred seven and six years before, respectively. She also suffered from moderate, well treated post-menopausal systemic hypertension. Post-mortem examination showed apical biventricular ballooning of the heart with no cardiac rupture, coronary artery lesion or other cardiac/extra-cardiac disease...
November 9, 2019: Forensic Science, Medicine, and Pathology
Masahiro Fujii, Keisuke Ota, Ryuzo Bessho
BACKGROUND: Hyperkalemic cardioplegia using St. Thomas' Hospital solution No. 2 (STH2) is commonly used to protect the myocardium during surgery. Mice deficient in the myocyte channel aquaporin 7 (AQP7) show significantly reduced glycerol and ATP contents and develop obesity; however, the influence of AQP7 on cardioplegia effectiveness remains unclear. METHODS: After determining the influence of ischemic duration on cardiac function, isolated hearts of male wild-type (WT) and AQP7-knockout (KO) mice (> 13 weeks old) were aerobically Langendorff-perfused with bicarbonate buffer, and randomly allocated to the control group (25 min of global ischemia) and STH2 group (5 min of STH2 infusion before 20 min of global ischemia, followed by 60 min of reperfusion)...
November 9, 2019: General Thoracic and Cardiovascular Surgery
Anja Karlstaedt, Radhika Khanna, Manoj Thangam, Heinrich Taegtmeyer
Rationale: Metabolic and structural remodeling is a hallmark of heart failure. This remodeling involves activation of the mammalian target of rapamycin (mTOR) signaling pathway, but little is known on how intermediary metabolites are integrated as metabolic signals. Objective: We investigated the metabolic control of cardiac glycolysis and explored the potential of glucose 6-phosphate to regulate glycolytic flux and mTOR activation. Methods and Results: We developed a kinetic model of cardiomyocyte carbohydrate metabolism, CardioGlyco, to study the metabolic control of myocardial glycolysis and glucose 6-phosphate levels...
November 8, 2019: Circulation Research
Qilin Sun, Xiaoyan Wu, Hao Wang, Wenjie Chen, Xuelan Zhao, Yehong Yang, Wei Chen
Background: Oxidative stress in cardiac myocytes is an important pathogenesis of diabetic cardiomyopathy (DCM). Previously, we reported that astragalus polysaccharide (APS) has protective effects against the oxidative stress of DCM. This study aimed to determine the effect of APS on the oxidative stress induced by hyperglycemia in H9C2 cells. Methods: Rat H9C2 cells were cultured in vitro and randomly divided into the control group, HG group, APS-HG group, siRNASOD2 group, and APS-siRNASOD2 group...
2019: Diabetes, Metabolic Syndrome and Obesity
Asma Mohammed Alyahya, Abeer Al-Masri, Ahmad Hersi, Eman El Eter, Sufia Husain, Rahmatunnesa Lateef, Ola H Mawlana
BACKGROUND Progranulin is an adipokine, encoded by the progranulin (GRN) gene. Progranulin is expressed in atherosclerosis, but its effects in cardiac ischemia and reperfusion injury are unknown. Therefore, this study aimed to investigate the effects of progranulin in a rat model of acute myocardial ischemia/reperfusion (MI/R) injury in vivo. MATERIAL AND METHODS The model of acute MI/R injury was established in male Wistar rats by ligation of the left anterior descending (LAD) coronary artery for 30 minutes and reperfusion for 60 minutes...
November 7, 2019: Medical Science Monitor Basic Research
Yuho Kim, Eric Lindberg, Christopher K E Bleck, Brian Glancy
No abstract text is available yet for this article.
November 5, 2019: Cardiovascular Research
Xudong Chen, Haiyan Li, Kangwei Wang, Xiaohe Liang, Weiqi Wang, Xiaokang Hu, Zhouqing Huang, Yonghua Wang
Background: High-fat-diet (HFD) is associated with chronic low-grade inflammation. P2X7 purinergic receptors (P2X7R) are key regulators of inflammasome activation. The benefits of exercise are partly attributed to its anti-inflammatory effect, but whether it regulates P2X7R expression to improve remodeling in cardiac myocytes treated by HFD is not completely clarified. Methods: Three groups of Sprague-Dawley (SD) rats were studied: (1) control group (fed a normal chow diet), (2) HFD group, and (3) HFD+ exercise group...
2019: Frontiers in Physiology
Dominic G Whittaker, Alan P Benson, Irvin Teh, Jürgen E Schneider, Michael A Colman
Cardiac electrical excitation-propagation is influenced by myocyte orientations (cellular organization). Quantitatively understanding this relationship presents a significant research challenge, especially during arrhythmias in which excitation patterns become complex. Tissue-scale simulations of cardiac electrophysiology, incorporating both dynamic action potential behavior and image-based myocardial architecture, provide an approach to investigate three-dimensional (3D) propagation of excitation waves in the heart...
October 8, 2019: Biophysical Journal
Minna Hassinen, Hanna Korajoki, Denis Abramochkin, Pavel Krivosheya, Matti Vornanen
Inward rectifier K+ (Kir2) channels are critical for electrical excitability of cardiac myocytes. Here, we examine expression of Kir2 channels in the heart of three Gadiformes species, polar cod (Boreogadus saida) and navaga (Eleginus nawaga) of the Arctic Ocean and burbot (Lota lota) of the temperate lakes to find out the role of Kir2 channels in cardiac adaptation to cold. Five boreal freshwater species: brown trout (Salmo trutta fario), arctic char (Salvelinus alpinus), roach (Rutilus rutilus), perch (Perca fluviatilis) and pike (Esox lucius), and zebrafish (Danio rerio), were included for comparison...
November 2, 2019: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Kristofer J Haushalter, Jan M Schilling, Young Song, Mira Sastri, Guy A Perkins, Stefan Strack, Susan S Taylor, Hemal H Patel
Type I PKA regulatory subunit alpha (RIα; encoded by the Prkar1a gene) serves as the predominant inhibitor protein of the catalytic subunit of cAMP-dependent protein kinase (PKAc). However, recent evidence suggests that PKA signaling can be initiated by cAMP-independent events, especially within the context of cellular oxidative stress such as ischemia/reperfusion (I/R) injury. We determined whether RIα is actively involved in the regulation of PKA activity via Reactive Oxygen Species (ROS) dependent mechanisms during I/R stress in the heart...
November 1, 2019: American Journal of Physiology. Heart and Circulatory Physiology
Karanjit Puri, Nathaniel Lal, Rui Shang, Sanjoy Ghosh, Stephane Flibotte, Roger Dyer, Bahira Hussein, Brian Rodrigues
Background Fatty acid (FA) provision to the heart is from cardiomyocyte and adipose depots, plus lipoprotein lipase action. We tested how a graded reduction in insulin impacts the source of FA used by cardiomyocytes and the cardiac adaptations required to process these FA. Methods and Results Rats injected with 55 (D55) or 100 (D100) mg/kg streptozotocin were terminated after 4 days. Although D55 and D100 were equally hyperglycemic, D100 showed markedly lower pancreatic and plasma insulin and loss of lipoprotein lipase, which in D55 hearts had expanded...
November 5, 2019: Journal of the American Heart Association
Leroy C Joseph, Uma Mahesh R Avula, Elaine Y Wan, Michael V Reyes, Kundanika R Lakkadi, Prakash Subramanyam, Koki Nakanishi, Shunichi Homma, Antoine Muchir, Utpal B Pajvani, Edward B Thorp, Steven R Reiken, Andrew R Marks, Henry M Colecraft, John P Morrow
BACKGROUND: Obesity and diets high in saturated fat increase the risk of arrhythmias and sudden cardiac death. However, the molecular mechanisms are not well understood. We hypothesized that an increase in dietary saturated fat could lead to abnormalities of calcium homeostasis and heart rhythm by a NOX2 (NADPH oxidase 2)-dependent mechanism. METHODS: We investigated this hypothesis by feeding mice high-fat diets. In vivo heart rhythm telemetry, optical mapping, and isolated cardiac myocyte imaging were used to quantify arrhythmias, repolarization, calcium transients, and intracellular calcium sparks...
November 2019: Circulation. Arrhythmia and Electrophysiology
Dustin T Yates, Leticia E Camacho, Amy C Kelly, Leah V Steyn, Melissa A Davis, Andrew T Antolic, Miranda J Anderson, Ravi Goyal, Ronald E Allen, Klearchos K Papas, William W Hay, Sean W Limesand
KEY POINTS: Previous studies in fetuses with intrauterine growth restriction (IUGR) have shown that adrenergic dysregulation was associated with low insulin concentrations and greater insulin sensitivity. Although whole-body glucose clearance is normal, one-month-old lambs with IUGR at birth have higher rates of hindlimb glucose uptake, which may compensate for myocyte deficiencies in glucose oxidation. Impaired glucose-stimulated insulin secretion in IUGR lambs is due to lower intra-islet insulin availability and not from glucose sensing...
October 30, 2019: Journal of Physiology
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