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ROS and arrhythmias

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https://www.readbyqxmd.com/read/29736684/regional-increase-in-ros-within-stretched-region-exacerbates-arrhythmias-in-rat-trabeculae-with-nonuniform-contraction
#1
Masahito Miura, Yuhto Taguchi, Tetsuya Handoh, Taiki Hasegawa, Yui Takahashi, Natsuki Morita, Ayana Matsumoto, Haruka Sato, Chiyohiko Shindoh
In diseased hearts, impaired muscle within the hearts is passively stretched by contractions of the more viable neighboring muscle during the contraction phase. We investigated whether in the myocardium with nonuniform contraction such passive stretch regionally generates ROS within the stretched region and exacerbates arrhythmias. In trabeculae from rat hearts, force, intracellular Ca2+ , and membrane potential were measured. To assess regional ROS generation, the slope of the change in the 2',7'-dichlorofluorescein fluorescence (DCFslope ) was calculated at the each pixel position along the long axis of trabeculae using DCF fluorescence images...
May 8, 2018: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29668881/hyperactive-ryanodine-receptors-in-human-heart-failure-and-ischemic-cardiomyopathy-reside-outside-of-couplons
#2
Eef Dries, Demetrio J Santiago, Guillaume Gilbert, Ilse Lenaerts, Bert Vandenberk, Chandan K Nagaraju, Daniel M Johnson, Patricia Holemans, H Llewelyn Roderick, Niall Macquaide, Piet Claus, Karin R Sipido
Aims: In ventricular myocytes from humans and large mammals, the transverse and axial tubular system (TATS) network is less extensive than in rodents with consequently a greater proportion of ryanodine receptors (RyRs) not coupled to this membrane system. TATS remodeling in heart failure (HF) and after myocardial infarction (MI) increases the fraction of non-coupled RyR. Here we investigate whether this remodeling alters the activity of coupled and non-coupled RyR sub-populations through changes in local signaling...
April 14, 2018: Cardiovascular Research
https://www.readbyqxmd.com/read/29643809/examination-of-the-role-of-mitochondrial-morphology-and-function-in-the-cardioprotective-effect-of-sodium-nitrite-administered-24-h-before-ischemia-reperfusion-injury
#3
Vivien Demeter-Haludka, Mária Kovács, Alexandra Petrus, Roland Patai, Danina M Muntean, László Siklós, Ágnes Végh
Background: We have previous evidence that in anesthetized dogs the inorganic sodium nitrite protects against the severe ventricular arrhythmias, resulting from coronary artery occlusion and reperfusion, when administered 24 h before. The present study aimed to examine, whether in this effect changes in mitochondrial morphology and function would play a role. Methods: Thirty dogs were infused intravenously either with saline ( n = 15) or sodium nitrite (0.2 μmol/kg/min; n = 15) for 20 min, and 24 h later, 10 dogs from each group were subjected to a 25 min period of occlusion and then reperfusion of the left anterior descending coronary artery...
2018: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29625277/the-loss-of-p21-activated-kinase-pak1-promotes-atrial-arrhythmic-activity-the-role-of-pak1-in-atrial-arrhythmia
#4
Jaime DeSantiago, Dan J Bare, Disha Varma, R John Solaro, Rishi Arora, Kathrin Banach
BACKGROUND: Atrial fibrillation (AF) is initiated through arrhythmic atrial excitation from outside the sinus node or remodeling of atrial tissue that allows reentry of excitation. Angiotensin II (AngII) has been implicated in initiation and maintenance of AF through changes in Ca2+ handling and production of reactive oxygen species (ROS). OBJECTIVE: We aimed to determine the role of Pak1, a downstream target in the AngII signaling cascade, in atrial electrophysiology and arrhythmia...
April 3, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29491325/protective-effects-of-topiroxostat-on-an-ischemia-reperfusion-model-of-rat-hearts
#5
Shogo Tanno, Kenshiro Yamamoto, Yasutaka Kurata, Maya Adachi, Yumiko Inoue, Naoyuki Otani, Mutsuo Mishima, Yasutaka Yamamoto, Masanari Kuwabara, Kazuhide Ogino, Junichiro Miake, Haruaki Ninomiya, Yasuaki Shirayoshi, Futoshi Okada, Kazuhiro Yamamoto, Ichiro Hisatome
BACKGROUND: Ischemia/reperfusion (I/R) injury triggers cardiac dysfunctions via creating reactive oxygen species (ROS). Because xanthine oxidase (XO) is one of the major enzymes that generate ROS, inhibition of XO is expected to suppress ROS-induced I/R injury. However, it remains unclear whether XO inhibition really yields cardioprotection during I/R. The protective effects of the XO inhibitors, topiroxostat and allopurinol, on cardiac I/R injury were evaluated.Methods and Results:Using isolated rat hearts, ventricular functions, occurrence of arrhythmias, XO activities and thiobarbituric acid reactive substances (TBARS) productions and myocardial levels of adenine nucleotides before and after I/R, and cardiomyocyte death markers during reperfusion, were evaluated...
March 23, 2018: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/29453615/vidarabine-an-anti-herpesvirus-agent-prevents-catecholamine-induced-arrhythmias-without-adverse-effect-on-heart-function-in-mice
#6
Kenji Suita, Takayuki Fujita, Wenqian Cai, Yuko Hidaka, Huiling Jin, Rajesh Prajapati, Masanari Umemura, Utako Yokoyama, Motohiko Sato, Björn C Knollmann, Satoshi Okumura, Yoshihiro Ishikawa
Sympathetic activation causes clinically important arrhythmias including atrial fibrillation (AF) and ventricular tachyarrhythmia. Although the usefulness of β-adrenergic receptor blockade therapy is widely accepted, its multiple critical side effects often prevent its initiation or continuation. The aim of this study is to determine the advantages of vidarabine, an adenylyl cyclase (AC)-targeted anti-sympathetic agent, as an alternative treatment for arrhythmia. We found that vidarabine, which we identified as a cardiac AC inhibitor, consistently shortens AF duration and reduces the incidence of sympathetic activation-induced ventricular arrhythmias...
February 16, 2018: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29410242/sr-ca-2-leak-and-disordered-excitation-contraction-coupling-as-the-basis-for-arrhythmogenic-and-negative-inotropic-effects-of-acute-ethanol-exposure
#7
Julian Mustroph, Olivia Wagemann, Simon Lebek, Daniel Tarnowski, Jasmin Ackermann, Marzena Drzymalski, Steffen Pabel, Christof Schmid, Stefan Wagner, Samuel Sossalla, Lars S Maier, Stefan Neef
AIMS: Ethanol has acute negative inotropic and arrhythmogenic effects. The underlying mechanisms, however, are largely unknown. Sarcoplasmic reticulum Ca2+ -leak is an important mechanism for reduced contractility and arrhythmias. Ca2+ -leak can be induced by oxidative stress and Ca2+ /Calmodulin-dependent protein kinase II (CaMKII). Therefore, we investigated the influence of acute ethanol exposure on excitation-contraction coupling in atrial and ventricular cardiomyocytes. METHODS AND RESULTS: Isolated human atrial and murine atrial or ventricular cardiomyocytes were preincubated for 30 min and then superfused with control solution or solution containing ethanol...
March 2018: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29407091/estradiol-protection-against-toxic-effects-of-catecholamine-on-electrical-properties-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#8
Ibrahim El-Battrawy, Zhihan Zhao, Huan Lan, Jan-Dierk Schünemann, Katherine Sattler, Fanis Buljubasic, Bence Patocskai, Xin Li, Gökhan Yücel, Siegfried Lang, Daniel Nowak, Lukas Cyganek, Karen Bieback, Jochen Utikal, Wolfram-Hubertus Zimmermann, Ursula Ravens, Thomas Wieland, Martin Borggrefe, Xiao-Bo Zhou, Ibrahim Akin
BACKGROUND AND PURPOSE: Previous studies revealed that Takotsubo cardiomyopathy (TTC), a transient disorder of ventricular dysfunction affecting predominantly postmenopausal women, is associated with acquired long QT syndrome and arrhythmias, but the exact pathophysiologic mechanism is unknown. Our aim is to investigate the electrophysiological mechanism for QT-prolongation in TTC-patients by using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). METHODS: hiPSC-CMs, which were generated from human skin fibroblasts of three healthy donors, were treated by estradiol (10μM for one week) and a toxic concentration of isoprenaline (Iso, 1mM for 2h)...
March 1, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/28925721/the-more-effective-treatment-of-atrial-fibrillation-applying-the-natural-compounds-as-nadph-oxidase-and-ion-channel-inhibitors
#9
Samira Barangi, A Wallace Hayes, Gholamreza Karimi
Atrial fibrillation (AF) is the most common cardiac arrhythmia that occurs because of several different risk factors, e.g., valvular heart disease, coronary artery disease, age ≥75 years, hypertension and diabetes mellitus. One key risk factor that results in AF, is oxidative stress. Evidence suggests that there is a correlation between oxidative processes and the genesis of AF. Oxidative stress occurs when the generation of reactive oxygen species (ROS) increase due to excessive activity of enzymes including NADPH oxidase (NOX) and xanthine oxidase; or its degradation decrease by dysfunctional antioxidant enzyme systems, such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx)...
September 19, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28888367/attenuation-of-ischemia-reperfusion-induced-inhibition-of-the-rapid-component-of-delayed-rectifier-potassium-current-by-isosteviol-through-scavenging-reactive-oxygen-species
#10
Chunxia Yin, Yaoxu Chen, Huanlin Wu, Danping Xu, Wen Tan
Isosteviol has been demonstrated to play a protective role during ischemia reperfusion (I/R) myocardial infarction. However, the underlying electrophysiological mechanisms of isosteviol are still unknown. Our previous study showed that the rapid component of the delayed rectifier potassium channel (IKr ) plays an important role in the prolongation of I/R-induced QT interval-related arrhythmia. This study aimed to investigate whether isosteviol could attenuate I/R-induced prolongation of the action potential duration (APD) along with inhibition of IKr , and we aimed to clarify the electrophysiological mechanism of isosteviol to determine its cardioprotective effects in guinea pigs...
December 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28871102/angiotensin-ii-affects-inflammation-mechanisms-via-ampk-related-signalling-pathways-in-hl-1-atrial-myocytes
#11
Nami Kim, Youngae Jung, Miso Nam, Mi Sun Kang, Min Kyung Lee, Youngjin Cho, Eue-Keun Choi, Geum-Sook Hwang, Hyeon Soo Kim
Inflammation is a common cause of cardiac arrhythmia. Angiotensin ІІ (Ang ІІ) is a major contributing factor in the pathogenesis of cardiac inflammation; however, its underlying molecular mechanism remains unclear. Here, we explored the effect of Ang ІІ on inflammatory mechanisms and oxidative stress using HL-1 atrial myocytes. We showed that Ang ІІ activated c-Jun N-terminal kinase (JNK) phosphorylation and other inflammatory markers, such as transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α)...
September 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28683969/impact-of-oxidative-stress-on-the-heart%C3%A2-and-vasculature-part-2-of-a-3-part-series
#12
REVIEW
Thomas Münzel, Giovanni G Camici, Christoph Maack, Nicole R Bonetti, Valentin Fuster, Jason C Kovacic
Vascular disease and heart failure impart an enormous burden in terms of global morbidity and mortality. Although there are many different causes of cardiac and vascular disease, most causes share an important pathological mechanism: oxidative stress. In the failing heart, oxidative stress occurs in the myocardium and correlates with left ventricular dysfunction. Reactive oxygen species (ROS) negatively affect myocardial calcium handling, cause arrhythmia, and contribute to cardiac remodeling by inducing hypertrophic signaling, apoptosis, and necrosis...
July 11, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28670363/verapamil-suppresses-cardiac-alternans-and-ventricular-arrhythmias-in-acute-myocardial-ischemia-via-ryanodine-receptor-inhibition
#13
Yu-Lei Deng, Jun-Yan Zhao, Ji-Hua Yao, Qiang Tang, Le Zhang, Hong-Lian Zhou, Cun-Tai Zhang, Jia-Gao Lv, Xiao-Qing Quan
T-wave alternans (TWA) is a potent arrhythmia substrate under the conditions of acute myocardial ischemia. Abnormal intracellular calcium cycling contributes to the genesis of cardiac alternans. Ryanodine receptor (RyR) is a pivotal Ca(2+) cycling protein central to Ca(2+) signaling in the heart. Here, we investigated the potential role of RyR in cardiac alternans and ventricular arrhythmias in acute myocardial ischemia. Transmembrane action potentials were simultaneously recorded from epicardium and endocardium together with a transmural ECG and isometric contraction force in the arterially perfused left ventricular wedge preparations...
2017: American Journal of Translational Research
https://www.readbyqxmd.com/read/28646979/inhibition-of-rapid-delayed-rectifier-potassium-current-ikr-by-ischemia-reperfusion-and-its-recovery-by-vitamin-e-in-ventricular-myocytes
#14
Yaoxu Chen, Chunxia Yin, Yingying Yang, Zhuo Fan, Jinling Shang, Wen Tan
Ischemia/reperfusion (I/R) induces prolongation of QT interval and action potential duration (APD), which is a major cardiac electrical disorder in patients with arrhythmias. However, the mechanism of QT interval prolongation induced by I/R remains unclear. In the present study, we hypothesized that the rapid component of delayed rectifier potassium (IKr) channel plays an important role in I/R-induced QT interval prolongation. We observed a marked attenuation of IKr and a significant prolongation of action potential duration (APD) in a simulated I/R system with sodium dithionite (Na2S2O4) in ventricular myocytes of guinea pigs...
July 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28551783/mitochondrial-mutations-in-cardiac-disorders
#15
REVIEW
Sung Ryul Lee, Jin Han
Mitochondria individually encapsulate their own genome, unlike other cellular organelles. Mitochondrial DNA (mtDNA) is a circular, double-stranded, 16,569-base paired DNA containing 37 genes: 13 proteins of the mitochondrial respiratory chain, two ribosomal RNAs (rRNAs; 12S and 16S), and 22 transfer RNAs (tRNAs). The mtDNA is more vulnerable to oxidative modifications compared to nuclear DNA because of its proximity to ROS-producing sites, limited presence of DNA damage repair systems, and continuous replication in the cell...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28450904/camkii-the-molecular-villain-that-aggravates-cardiovascular-disease
#16
Peiying Zhang
Pathological remodeling of the myocardium is an integral part of the events that lead to heart failure (HF), which involves altered gene expression, disturbed signaling pathways and altered Ca(2+) homeostasis and the players involved in this process. Of particular interest is the chronic activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) isoforms in heart, which further aggravate the injury to myocardium. Expression and activity of CaMKII have been found to be elevated in various conditions of stressed myocardium and in different heart diseases in both animal models as well as heart patients...
March 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28369703/the-gap-junction-modifier-zp1609-decreases-cardiomyocyte-hypercontracture-following-ischaemia-reperfusion-independent-from-mitochondrial-connexin-43
#17
Kerstin Boengler, Marko Bulic, Rolf Schreckenberg, Klaus-Dieter Schlüter, Rainer Schulz
BACKGROUND AND PURPOSE: Dysregulation of gap junction-mediated cell coupling contributes to development of arrhythmias and myocardial damage after ischaemia/reperfusion (I/R). Connexin 43 (Cx43) is present at ventricular gap junctions and also in the mitochondria of cardiomyocytes. The dipeptide (2S, 4R)-1-(2-aminoacetyl)-4-benzamidopyrrolidine-2-carboxylic acid (ZP1609) has antiarrhythmic properties and reduces infarct size when given at reperfusion. However, it is unclear, whether ZP1609 targets Cx43-containing mitochondria and affects cardiomyocyte hypercontracture following I/R...
July 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28349259/effect-of-paroxetine-on-left-ventricular-remodeling-in-an-in-vivo-rat-model-of-myocardial-infarction
#18
Thomas Ravn Lassen, Jan Møller Nielsen, Jacob Johnsen, Steffen Ringgaard, Hans Erik Bøtker, Steen Buus Kristiansen
Left ventricular (LV) remodeling following a myocardial infarction (MI) involves formation of reactive oxygen species (ROS). Paroxetine, a selective serotonin reuptake inhibitor, has an antioxidant effect in the vascular wall. We investigated whether paroxetine reduces myocardial ROS formation and LV remodeling following a MI. In a total of 32 Wistar rats, MI was induced by a 30-min ligation of the left anterior descending artery followed by 7- or 28-day reperfusion. During the 28 days of reperfusion, LV remodeling was evaluated by magnetic resonance imaging (MRI) and echocardiography (n = 20)...
May 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28231545/aqueous-extract-of-cortex-dictamni-protects-h9c2-cardiomyocytes-from-hypoxia-reoxygenation-induced-oxidative-stress-and-apoptosis-by-pi3k-akt-signaling-pathway
#19
Lin Li, Yunfeng Zhou, Yanlin Li, Lili Wang, Lan Sun, Lidong Zhou, Hiderori Arai, Yun Qi, Yang Xu
Ischemia-reperfusion injury is the major manifestation of ischemic heart disease, which facilitates cardiac arrhythmias, heart failure and death. Oxidative stress and apoptosis have been involved in the pathogenesis of myocardial ischemia-reperfusion injury. Modern pharmacological studies have indicated that the extracts and active compounds of Cortex Dictamni exhibit antioxidative and cardiovascular protective activities. This study was designed to investigate the protective effect of aqueous extract of Cortex Dictamni (CDAE) on regulating hypoxia/reoxygenation (H/R)-induced cardiomyocytes oxidative stress and apoptosis...
May 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28126503/-pathophysiology-of-obstructive-sleep-apnea-syndrome-and-its-cardiometabolic-consequences
#20
REVIEW
Marie Destors, Renaud Tamisier, Louis-Marie Galerneau, Patrick Lévy, Jean-Louis Pepin
Obstructive sleep apnoea syndrome (OSAS) is characterized by recurrent partial or complete pharyngeal collapses during sleep. The pathophysiology of OSAS is complex and multifactorial. Factors influencing upper airway patency include a reduction in upper airway dimensions that can result from both anatomical and functional alterations (obesity, fluid shift or maxillo-facial structural changes), and increased pharyngeal collapsibility owing to reduced neuromuscular compensation and lack of the pharyngeal protective reflex during sleep...
April 2017: La Presse Médicale
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