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American Journal of Physiology. Heart and Circulatory Physiology

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https://www.readbyqxmd.com/read/29146615/-mighty-chondrial-dna-repair-for-mitigation-of-cardiac-injury-editorial-focus-on-h-00515-2017r1
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
https://www.readbyqxmd.com/read/29127234/ppar%C3%AE-agonists-acutely-inhibit-calcium-independent-pla2-to-reduce-h2o2-induced-contractions-in-aortae-of-spontaneously-hypertensive-rats
#8
Hui Chen, Ricky Y K Man, Susan W S Leung
Hypertension is associated with endothelial dysfunction, which favors the release of endothelium-derived contracting factors, including vasoconstrictor prostanoids and reactive oxygen species. Peroxisome proliferator-activated receptor α (PPARα) agonists, clinically used as lipid lowering drugs, possess antioxidant properties and exert beneficial effects in the vascular system. The present study aimed to identify the mechanism(s) underlying the acute effects of the PPARα agonists, Wy14643 and fenofibate, on endothelium-dependent contractions, in particular, those related to oxidative stress, in the aorta of the spontaneously hypertensive rat (SHR)...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29127233/vascular-endothelial-function-masks-increased-sympathetic-vasopressor-activity-in-rats-with-metabolic-syndrome
#9
Sylvain Battault, Cindy Meziat, Alessandro R Nascimento, Laura Braud, Sandrine Gayrard, Christian Legros, Frederic De Nardi, Jocelyne Drai, Olivier Cazorla, Jérôme Thireau, Gregory Meyer, Cyril Reboul
OBJECTIVE: Sympathetic hyperactivation, a common feature of obesity and metabolic syndrome, is a key trigger of hypertension. However, some obese subjects with autonomic unbalance present a dissociation between sympathetic activity mediated vasoconstriction and increased blood pressure. Here, we aimed to determine in a rat model of metabolic syndrome, whether the endothelium eNOS-NO pathway contribute to counteract the vasopressor effect of the sympathetic system. METHODS: Rats were fed a high fat and high sucrose diet for 15 weeks (HFS)...
November 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101185/advanced-oxidation-protein-products-aggravate-cardiac-remodeling-via-cardiomyocyte-apoptosis-in-chronic-kidney-disease
#10
Weijing Feng, Kun Zhang, Yu Liu, Jie Chen, Qingqing Cai, Wanbing He He, Yinyin Zhang, Mong-Heng Wang, Jingfeng Wang, Hui Huang
Advanced oxidation protein products (AOPPs) are independent risk factor for various cardiovascular diseases. Cardiomyocyte apoptosis has been implicated as an important mechanism in cardiac remodeling in chronic kidney disease (CKD). However, whether AOPPs affect cardiomyocyte apoptosis and subsequent cardiac remodeling in CKD is still not very clear. Here, we assessed the role of AOPPs in cardiomyocyte apoptosis in CKD. H9C2 rat cardiomyoblast cells were exposed to AOPPs. The apoptotic cells were determined by TUNEL assay...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101184/too-much-traffic-at-the-crossroads-of-diabetes-and-endothelial-dysfunction
#11
Zsolt Bagi
N/A.
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101183/the-pleiotropic-effects-of-hydrogen-sulfide
#12
Nancy L Kanagy, Christopher G Kevil
editorial on hydrogen sulfide...is there supposed to be an abstract?
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101182/mechanism-underlying-heart-rate-dependency-of-wave-reflection-in-the-aorta-a-numerical-simulation
#13
Hanguang Xiao, Isabella Tan, Mark Butlin, Decai Li, Alberto P Avolio
Arterial wave reflection has been shown to have a significant dependence on heart rate (HR). However, the underlying mechanisms inherent in the HR dependency of wave reflection have not been well established. This study aimed to investigate the potential mechanisms and the role of arterial viscoelasticity using a 55-segment transmission line model (TLM) of the human arterial tree combined with a fractional viscoelastic model (FVM). At varying degrees of viscoelasticity modeled as fractional order parameter α, reflection magnitude (RM), reflection index (RI), augmentation index (AIx) and a proposed novel normalized reflection coefficient (Γnorm) were estimated at different HRs from 60 to 100 beats per minute (bpm) with a constant mean flow of 70 ml/s...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101181/endothelial-dysfunction-is-a-super-inducer-of-syndecan-4-fibrogenic-role-of-its-ectodomain
#14
Mark Lipphardt, Jong W Song, Brian B Ratliff, Hassan Dihazi, Gerhard A Müller, Michael S Goligorsky
Syndecan 4 (Synd4) is a member of membrane-spanning, glycocalyx-forming proteoglycan family. It has been suggested that Synd4 participates in renal fibrosis. We compared wild type and fibrosis-prone endothelial sirtuin1-deficient (Sirt1(endo)-/-) mice, the latter being a model of global endothelial dysfunction. We performed mass-spectrometry analysis, which revealed that Synd4 was highly enriched in the secretome of renal microvascular endothelial cells (RMVEC) obtained from Sirt1(endo)-/- mice upon stimulation with TGFβ1; notably all detectable peptides were confined to the ectodomain of Synd4...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101180/reduced-longitudinal-contraction-is-associated-with-ischemic-mitral-regurgitation-after-posterior-mi
#15
Kiyotake Ishikawa, Shin Watanabe, Nadjib Hammoudi, Jaume Aguero, Olympia Bikou, Kenneth Fish, Roger J Hajjar
BACKGROUND: The role of left ventricular (LV) longitudinal contraction in ischemic mitral regurgitation (MR) remains unclear. We hypothesized that reduced longitudinal contraction disrupts normal mitral valve plane displacement during systole and leads to mitral valve tethering, thereby inducing ischemic MR. METHODS: Twenty-three Yorkshire pigs underwent induction of different-sized posterior myocardial infarction (MI) using a percutaneous approach. Incidence of MR and its association to LV longitudinal strain was examined using speckle-tracking echocardiography at one month post-MI to determine their relationship...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101179/reduced-membrane-cholesterol-following-chronic-hypoxia-limits-orai1-mediated-pulmonary-endothelial-ca-2-entry
#16
Bojun Zhang, Jay S Naik, Nikki L Jernigan, Benjimen R Walker, Thomas C Resta
Endothelial dysfunction in chronic hypoxia (CH)-induced pulmonary hypertension is characterized by reduced store-operated Ca(2+) entry (SOCE) and diminished Ca(2+)-dependent production of endothelium-derived vasodilators. We recently reported that SOCE in pulmonary arterial endothelial cells (PAEC) is tightly regulated by membrane cholesterol, and that decreased membrane cholesterol is responsible for impaired SOCE following CH. However, the ion channels involved in cholesterol-sensitive SOCE are unknown. We hypothesized that cholesterol facilitates SOCE in PAEC through the interaction of Orai1 and stromal interaction molecule 1 (STIM1)...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101178/heart-functional-and-structural-compendium-of-cardiosplenic-and-cardiorenal-networks-in-acute-and-chronic-heart-failure-pathology
#17
Ganesh V Halade, Vasundhara Kain, Kevin A Ingle
Heart failure (HF) secondary to myocardial infarction (MI) is linked to kidney complications that comprise cellular, structural, functional, and survival indicators. However, the HF research is focused on left ventricle (LV) pathology. Here, we determined the comprehensive functional analysis of LV using echocardiography in transition from acute HF (AHF) to progressive CHF pathology and develop a histological compendium of the cardiosplenic and cardiorenal networks in pathological remodeling. In surgically-induced MI using permanent coronary ligation, the LV dysfunction is pronounced, with myocardium necrosis, wall-thinning and 20-30% LV rupture events that indicated AHF and CHF pathological remodeling in C57BL/6 male mice (2-4 months old; n=50)...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101177/a-novel-mitochondrial-dna-repair-enzyme-attenuates-maladaptive-remodeling-and-preserves-cardiac-function-in-heart-failure
#18
Jessica M Bradley, Zhen Li, Chelsea L Organ, David J Polhemus, Hiroyuki Otsuka, Shashi Bhushan, Olena M Gorodnya, Mykhaylo Ruchko, Mark N Gillespie, Glenn L Wilson, David J Lefer
BACKGROUND: Oxidative stress results in mitochondrial DNA (mtDNA) damage and contributes to myocardial cell death. mtDNA repair enzymes are crucial for mtDNA repair and cell survival. We investigated a novel, mitochondrial-targeted fusion protein (Exscien1-III) containing endonuclease III in myocardial ischemia/reperfusion (MI/Rep) injury and transverse aortic constriction (TAC) induced heart failure. METHODS AND RESULTS: Male C57/BL6J mice (10-12 wks) were subjected to 45 min...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101176/vegf-nanoparticles-repair-heart-after-myocardial-infarction
#19
Yasin Oduk, Wuqiang Zhu, Ramaswamy Kannappan, Meng Zhao, Anton V Borovjagin, Suzanne Oparil, Jianyi Zhang
Vascular endothelial growth factor (VEGF) is a well characterized pro-angiogenic cytokine that has been shown to promote neovascularization in the hearts of patients with ischemic heart disease but can also lead to adverse effects, depending on the dose and mode of delivery. We investigated whether prolonged exposure to a low dose of VEGF could be achieved by encapsulating the VEGF in polylactic-co-glycolic acid (PLGA) nanoparticles and whether treatment with VEGF-containing nanoparticles improved cardiac function and protected against left ventricular (LV) remodeling in the hearts of mice with experimentally induced myocardial infarction (MI)...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29101175/loss-of-caveolin-3-dependent-regulation-of-ica-in-rat-ventricular-myocytes-in-heart-failure
#20
Simon M Bryant, Cherrie H T Kong, Mark B Cannell, Clive H Orchard, Andrew F James
β2-adrenoceptors and the L-type Ca current (ICa) redistribute from the t-tubules to the surface membrane of ventricular myocytes from failing hearts. The present study investigated the role of changes in caveolin-3 (Cav-3) and protein kinase A (PKA) signaling, both of which have previously been implicated in this redistribution. ICa was recorded using the whole cell patch clamp technique from ventricular myocytes isolated from the hearts of rats that had undergone either coronary artery ligation (CAL) or equivalent Sham operation 18 weeks earlier...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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