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American Journal of Physiology. Heart and Circulatory Physiology

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https://www.readbyqxmd.com/read/29212794/ferroptosis-beating-on-death-s-door
#1
Rimpy Dhingra, Amir Ravandi, Lorrie A Kirshenbaum
One of the most fascinating concepts to impact contemporary biology to date is the idea that cell death is a highly regulated and programmed event. Cardiac cells can die by apoptosis or necrosis and in some instances by autophagy. Ferroptosis, is a new form of regulated cell death that is gaining considerable attention, that links de-regulated iron metabolism with peroxidative lipid injury. In this report, we highlight a recent study by Baba et al that describes ferroptosis as regulated form of cell death in the heart...
December 6, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29212793/pacap-6-38-or-kynurenate-microinjections-into-the-rvlm-prevent-development-of-sympathetic-long-term-facilitation-following-acute-intermittent-hypoxia
#2
Zohra M Kakall, Paul M Pilowsky, Melissa Mj Farnham
BACKGROUND AND PURPOSE: Intermittent hypoxia causes a persistent increase in sympathetic activity, which progresses to hypertension in chronic conditions such as obstructive sleep apnea (OSA). Pituitary adenylate cyclase activating polypeptide (PACAP) is an excitatory neurotransmitter that causes long-lasting sympathetic excitation. We aimed to determine if intermittent activation of the rostral ventrolateral medulla (RVLM) causes PACAP-mediated elevation of sympathetic nerve activity (sSNA), termed sympathetic long-term facilitation (sLTF)...
December 6, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29212792/differential-effects-of-alcohol-and-its-metabolite-acetaldehyde-on-vascular-smooth-muscle-cell-notch-signaling-and-growth
#3
Ekaterina Hatch, David Morrow, Weimin Liu, Paul A Cahill, Eileen M Redmond
Alcohol (EtOH) consumption can variously affect cardiovascular disease (CVD). Our aim was to compare the effects of EtOH and its primary metabolite acetaldehyde (ACT) on vascular smooth muscle Notch signaling and cell growth that are important for atherogenesis. Human coronary artery smooth muscle cells (HCASMC) were treated with EtOH (25 mM) or ACT (10 μM, 25 μM). As previously reported, EtOH inhibited Notch signaling and growth of HCASMC. In contrast, ACT treatment stimulated HCASMC proliferation (cell counts) and increased proliferating cell nuclear antigen (PCNA) expression, concomitant with stimulation of Notch signaling as determined by increased Notch receptor (N1, N3) and target gene (HRT 1-3) mRNA levels...
December 6, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29212791/perinatal-inflammation-induces-sex-related-differences-in-cardiovascular-morbidities-in-mice
#4
Markus Velten, Kathryn Marie Heyob, Loren E Wold, Lynette K Rogers
Sex-related differences in cardiovascular health and disease have been identified with males having a higher incidence of cardiovascular events but females more likely to develop arrhythmias. Adverse fetal environments are now accepted as a cause for the development of cardiovascular diseases in adulthood but sex-related differences in response to adverse fetal environments have not been extensively explored. The combination of both in utero and postnatal exposure to inflammation is highly clinically relevant for the infant that is born preterm or has clinical complications at birth or early postnatal life...
December 6, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29196345/mitoprotection-attenuates-myocardial-vascular-impairment-in-porcine-metabolic-syndrome
#5
Fang Yuan, Ahmad F Hedayat, Christopher M Ferguson, Amir Lerman, Lilach O Lerman, Alfonso Eirin
INTRODUCTION: The metabolic syndrome (MetS) leads to cardiac vascular injury, which may reflect in increased retention of endothelial progenitor cells (EPC). Coronary endothelial cell (EC) mitochondria partly regulate vascular function and structure. We hypothesized that chronic mitoprotection would preserve EC mitochondria and attenuate coronary vascular injury and dysfunction in swine MetS. METHODS: Pigs were studied after 16 weeks of diet-induced MetS, MetS treated for the last 4 weeks with the mitochondria-targeted peptide elamipretide (ELAM, 0...
December 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29196344/differential-cardiac-hypertrophy-and-signaling-pathways-in-pressure-versus-volume-overload
#6
Jieyun You, Jian Wu, Qi Zhang, Yong Ye, Shijun Wang, Jiayuan Huang, Haibo Liu, Xiaoyan Wang, Weijing Zhang, Liping Bu, Jiming Li, Li Lin, Junbo Ge, Yunzeng Zou
OBJECTIVES: Mechanical overload can be classified into pressure overload and volume overload, causing concentric and eccentric cardiac hypertrophy, respectively. Here, we aimed to differentiate the load-mediated signaling pathways involved in pressure versus volume overload cardiac hypertrophy. METHODS: Pressure or volume overload was imposed on C57BL/6J mice by transverse aortic constriction (TAC), or aortic regurgitation (AR), respectively. Two weeks after surgery, left ventricular structure and function were evaluated by echocardiographic, hemodynamic and histological analyses...
December 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167123/lower-resting-and-exercise-induced-circulating-angiogenic-progenitors-and-angiogenic-t-cells-in-older-men
#7
Mark Daniel Ross, Eva M Malone, Richard Simpson, Islay Cranston, Lesley Ingram, Graham P Wright, George Chambers, Geraint D Florida-James
Ageing is associated with a dysfunctional endothelial phenotype, as well as reduced angiogenic capabilities. Exercise exerts beneficial effects on the cardiovascular system, possibly by increasing/maintaining the number and/or function of circulating angiogenic cells (CACs) that are known to decline with age. However, the relationship between cardiorespiratory fitness (CRF) and age related changes in frequency of CACs, as well as the exercise-induced responsiveness of CACs in older individuals has not yet been determined...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167122/burst-patterning-of-hypothalamic-paraventricular-nucleus-driven-sympathetic-nerve-activity-in-angiotensin-ii-salt-hypertension
#8
Walter W Holbein, Megan Bardgett Blackburn, Mary Ann Andrade, Glenn M Toney
Angiotensin II-salt hypertension (AngII-salt HTN) selectively increases splanchnic sympathetic nerve activity (sSNA), but the extent to which this reflects increased respiratory versus cardiac rhythmic bursting is unknown. Here, integrated sSNA was elevated in AngII infused rats fed a high salt (2% NaCl) diet (AngII-HSD) compared to vehicle infused rats fed a normal salt (0.4% NaCl) diet (Veh-NSD) (P<0.01). Increased sSNA was not accompanied by increased inspiratory or expiratory bursting, consistent with no group difference in central inspiratory drive...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167121/flow-mediated-dilation-stimulated-by-sustained-increases-in-shear-stress-a-useful-tool-for-assessing-endothelial-function-in-humans
#9
Joshua C Tremblay, Kyra Ellen Pyke
Investigations of human conduit artery endothelial function via flow-mediated vasodilation (FMD) have largely been restricted to the reactive hyperemia (RH) technique, wherein a transient increase in shear stress following the release of limb occlusion stimulates upstream conduit artery vasodilation (RH-FMD). FMD can also be assessed in response to sustained increases in shear stress (sustained stimulus (SS)-FMD), most often created with limb heating or exercise. Exercise in particular creates a physiologically-relevant stimulus because shear stress increases, and FMD occurs, during typical day-to-day activity...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167120/acute-lysyl-oxidase-inhibition-alters-microvascular-function-in-normotensive-but-not-hypertensive-men-and-women
#10
Daniel H Craighead, Huilei Wang, Lakshmi Santhanam, Lacy M Alexander
The Lysyl oxidase (LOX) family of enzymes regulates collagen cross-linking. LOX is upregulated in hypertension, increasing vascular stiffness. In vivo human research is sparse as long-term LOX inhibition in animals causes vascular instability. Our aim was to evaluate the effects of LOX inhibition on cutaneous microvascular function to determine if LOX function was upregulated in hypertensive humans. Four intradermal microdialysis fibers were placed in the forearm of 10 young (age: 24±1 y, MAP: 87±2 mmHg), 10 normotensive (age: 50±2 y, MAP: 84±1 mmHg), and 10 hypertensive (age: 53±2 y, MAP 112±2 mmHg) subjects...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167119/revisiting-the-physiological-effects-of-exercise-training-on-autonomic-regulation-and-chemoreflex-control-in-heart-failure-does-ejection-fraction-matter
#11
David Cristobal Andrade, Alexis Arce-Alvarez, Camilo Toledo, Hugo S Diaz, Claudia Lucero, Rodrigo Quintanilla, Harold D Schultz, Noah J Marcus, Markus Amman, Rodrigo Del Rio
Heart failure (HF) is a global public health problem that, independent of its etiology (reduced (HFrEF) or preserved ejection fraction (HFpEF)), is characterized by functional impairments of cardiac function, chemoreflex hypersensitivity, baroreflex sensitivity (BRS) impairment, and abnormal autonomic regulation, all of which contribute to increased morbidity and mortality. Exercise training (ExT) has been identified as a nonpharmacological therapy capable of restoring normal autonomic function and improving survival in patients with HFrEF...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167118/exercise-facilitates-early-recognition-of-cardiac-and-vascular-remodeling-in-chronic-thrombo-embolic-pulmonary-hypertension-in-a-novel-cteph-swine-model
#12
Kelly Stam, Richard W B van Duin, Andre Uitterdijk, Zongye Cai, Dirk J Duncker, Daphne Merkus
Chronic thrombo-embolic pulmonary hypertension (CTEPH) develops in 4% of patients after pulmonary embolism and is accompanied by an impaired exercise tolerance, which is ascribed to the increased right ventricular (RV) afterload and a ventilation/perfusion (V/Q) mismatch in the lungs. This study investigated changes in arterial PO2 and hemodynamics in response to graded treadmill exercise during development and progression of CTEPH in a swine model. Swine were chronically instrumented and received multiple pulmonary embolisms by (i) microsphere infusion (Spheres) over five weeks, (ii) endothelial dysfunction by administration of eNOS inhibitor L-Nω-Nitroarginine methyl ester (LNAME) during seven weeks, (iii) combined pulmonary embolisms and endothelial dysfunction (LNAME+Spheres), or (iv) served as sham-operated controls (Sham)...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29167117/effect-of-6-weeks-of-high-intensity-one-legged-cycling-on-functional-sympatholysis-and-atp-signaling-in-patients-with-heart-failure
#13
Gregers Wibe Munch, Ulrik Winning Iepsen, Camilla Koch Ryrsø, Jaya Birgitte Rosenmeier, Bente Klarlund Pedersen, Stefan P Mortensen
Breathlessness during daily activities is the primary symptom in patients with heart failure (HF). Poor correlation between the hemodynamic parameters of left ventricular performance and perceived symptoms suggests that other factors such as skeletal muscle function plays a role in determining exercise capacity. We investigated the effect of six weeks of high-intensity one-legged cycling (HIC; 8x4 at 90% one-legged cycling max) on: 1) the ability to override sympathetic vasoconstriction (arterial infusion of tyramine) during one-legged knee-extensor exercise (KEE); 2) vascular function (arterial infusion of ACh, SNP, tyramine and ATP); 3) exercise capacity in HF patients with reduced ejection fraction (n=8) compared with healthy individuals (n=6)...
November 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29146615/-mighty-chondrial-dna-repair-for-mitigation-of-cardiac-injury-editorial-focus-on-h-00515-2017r1
#14
Qun Chen, Fadi N Salloum
No abstract text is available yet for this article.
November 16, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29146614/heart-rate-reduction-improves-biventricular-function-and-interactions-in-experimental-pulmonary-hypertension
#15
Olga Gomez, Kenichi Okumura, Osami Honjo, Mei Sun, Ryo Ishii, Bart Bijens, Mark K Friedberg
OBJECTIVES: To investigate mechanisms of heart rate (HR) reduction on biventricular function and interactions in experimental pulmonary arterial hypertension (PAH). METHODS: We compared cardiac-cycle mechanics and interventricular interactions in 15 sham, 8 monocrotaline-PAH, 9 PAH+carvedilol and 8 PAH+ivabradine rats. We used echocardiography to assess biventricular function, timing of cardiac- cycle events and septal position in PAH rats; and related HR reduction effect on biventricular function measured by echocardiography and conductance catheter...
November 16, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127239/a-novel-method-for-quantitative-myocardial-contrast-echocardiography-in-mice
#16
Erika Alvarez, Nancy D Dalton, Yusu Gu, Dan Smith, Alice Luong, Masahiko Hoshijima, Kirk L Peterson, Joshua Rychak
The small size of the mouse heart frequently imparts technical challenges when applying conventional in vivo imaging methods for assessing heart function. Here we describe the use of high frequency ultrasound imaging in conjunction with a size-tuned blood pool contrast agent for quantitatively assessing myocardial perfusion in living mice. A perflurocarbon microbubble formulation exhibiting a narrow size distribution was developed, and echogenicity assessed at 18 MHz in vitro. Adult mice were subjected to permanent ligation of the left anterior descending artery...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127238/protective-effects-of-the-mechanistic-target-of-rapamycin-against-excess-iron-and-ferroptosis-in-cardiomyocytes
#17
Yuichi Baba, Jason K Higa, Briana K Shimada, Kate M Horiuchi, Tomohiro Suhara, Motoi Kobayashi, Jonathan D Woo, Hiroko Aoyagi, Karra S Marh, Hiroaki Kitaoka, Takashi Matsui
Clinical studies suggest that myocardial iron is a risk factor for left ventricular remodeling in patients after myocardial infarction (MI). Ferroptosis was recently reported as a mechanism of iron-dependent non-apoptotic cell death. However, ferroptosis in the heart is not well understood. The mechanistic target of rapamycin (mTOR) protects the heart against pathological stimuli such as ischemia. To define the role of cardiac mTOR on cell survival in iron-mediated cell death, we examined cardiomyocyte (CM) cell viability under excess iron and ferroptosis conditions...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127237/metaboreflex-mediated-hemodynamic-abnormalities-in-individuals-with-coronary-artery-disease-without-overt-signs-or-symptoms-of-heart-failure
#18
Sara Magnani, Silvana Roberto, Gianmarco Sainas, Raffaele Milia, Girolamo Palazzolo, Lucia Cugusi, Virginia Pinna, Azzurra Doneddu, Seyed Alireza Hosseini Kakhak, Filippo Tocco, Giuseppe Mercuro, Antonio Crisafulli
This study was devised to investigate the effect of coronary artery disease (CAD) without overt signs of heart failure on the cardiovascular responses to muscle metaboreflex activation. We hypothesized that any CAD-induced pre-clinical systolic and/or diastolic dysfunction could impair hemodynamic response to the metaboreflex test. Twelve males diagnosed with CAD without any sign or symptoms of heart failure and 11 age-matched healthy controls (CTL) participated in the study. Subjects performed a post-exercise muscle ischemia (PEMI) test to activate the metaboreflex...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127236/structural-and-functional-changes-of-the-pulmonary-vasculature-after-hypoxia-exposure-in-the-neonatal-period-a-new-swine-model-of-pulmonary-vascular-disease
#19
Daphne P M de Wijs-Meijler, Richard W B van Duin, Dirk J Duncker, Urs Scherrer, Claudio Sartori, Irwin K M Reiss, Daphne Merkus
Pulmonary vascular disease (PVD) represents an underestimated and increasing clinical burden in the neonatal period, but also later in life, when exercise-tolerance is decreased. Animal models performing long-term follow-up after a perinatal insult are lacking. This study aimed to develop and characterize a neonatal swine model with hypoxia-induced PVD, during long-term follow-up after re-exposure to normoxia, and to investigate the exercise response in this model. Piglets were exposed to a normoxic (N=10) or hypoxic environment (N=9) for four weeks...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127235/cardiac-performance-is-limited-by-oxygen-delivery-to-the-mitochondria-in-the-crystalloid-perfused-working-heart
#20
Sarah Kuzmiak-Glancy, Raul Covian, Armel N Femnou, Brian Glancy, Rafael Jaimes, Anastasia M Wengrowski, Kara Garrott, Stephanie French, Robert S Balaban, Matthew W Kay
The left ventricular (LV) working, crystalloid-perfused heart is used extensively to evaluate basic cardiac function, pathophysiology, and pharmacology. Crystalloid-perfused hearts may be limited by oxygen delivery, as adding oxygen carriers increases myoglobin oxygenation and improves myocardial function. However, whether decreased myoglobin oxygen saturation impacts oxidative phosphorylation (OxPhos) is unresolved since myoglobin has a much lower affinity for oxygen than cytochrome c oxidase (COX). In the present study, a laboratory-based synthesis of an affordable perfluorocarbon (PFC) emulsion was developed to increase perfusate oxygen-carrying capacity without impeding optical absorbance assessments...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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