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American Journal of Physiology. Heart and Circulatory Physiology

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https://www.readbyqxmd.com/read/28916639/small-rna-seq-during-acute-maximal-exercise-reveal-rnas-involved-in-vascular-inflammation-and-cardiometabolic-health
#1
Ravi Shah, Ashish S Yeri, Avash Das, Amanda Courtright-Lim, Olivia Ziegler, Ernest Gervino, Jeffrey Ocel, Pablo Quintero Pinzon, Luke Wooster, Cole Shields Bailey, Kahraman Tanriverdi, Lea Beaulieu, Jane E Freedman, Ionita Ghiran, Gregory D Lewis, Kendall Van Keuren-Jensen, Saumya Das
OBJECTIVE: Exercise improves cardiometabolic and vascular function, though mechanisms remain unclear. Our objective was to demonstrate the diversity of circulating extracellular RNA (ex-RNA) release during acute exercise in humans and its relevance to exercise-mediated benefits on vascular inflammation. Approach and Results: We performed plasma small RNA sequencing (RNA-seq) in 26 individuals undergoing symptom-limited maximal treadmill exercise, with replication of our top candidate miRNA in a separate cohort of 59 individuals undergoing bicycle ergometry...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28916638/pharmacological-and-physiological-assessment-of-serotonin-formation-and-degradation-in-isolated-preparations-from-mouse-and-human-heart
#2
Ulrich Gergs, Franziska Jung, Igor B Buchwalow, Britt Hofmann, Andreas Simm, Hendrik Treede, Joachim Neumann
Using transgenic mice (TG) that overexpress the human 5-HT4a-receptor specifically in cardiomyocytes, we wanted to know whether 5-HT can be formed and degraded in the mammalian heart and whether this can likewise lead to inotropic and chronotropic effects in this TG model. We noted that the 5-HT precursor, 5-hydroxy-tryptophan (5-HTP), can exert inotropic and chronotropic effects in cardiac preparations from TG but not from wild type (WT): similar results were found in human atrial preparations, as well as in intact TG animals using echocardiography...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28916637/effect-of-increases-in-cardiac-contractility-on-cerebral-blood-flow-in-humans
#3
Shigehiko Ogoh, Gilbert Moralez, Takuro Washio, Satyam Sarma, Michinari Hieda, Steven A Romero, Matthew N Cramer, Manabu Shibasaki, Craig G Crandall
The effect of acute increases in cardiac contractility on cerebral blood flow (CBF) remains unknown. We hypothesized that the external carotid artery (ECA) downstream vasculature modifies the direct influence of acute increases in heart rate and cardiac function on CBF regulation. Twelve healthy subjects received two infusions of dobutamine (first a low dose; 5 μg/kg/min and then a high dose; 15 μg/kg/min) for 12 min each. Cardiac output, blood flow through the internal carotid artery (ICA) and ECA and echocardiographic measurements were performed during dobutamine infusions...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28916636/electrophysiological-heterogeneity-of-pacemaker-cells-in-rabbit-intercaval-region-including-sa-node-insights-from-recording-multiple-ion-currents-in-each-cell
#4
Oliver Monfredi, Kenta Tsutsui, Bruce D Ziman, Michael D Stern, Edward G Lakatta, Victor A Maltsev
Cardiac pacemaker cells, including cells of the sinoatrial node, are heterogeneous in size, morphology and electrophysiological characteristics. The exact extent to which these cells differ electrophysiologically is unclear, yet is critical to understanding their functioning. We examined major ionic currents in individual intercaval pacemaker cells (IPC) sampled from the para-cristal, inter-caval region (including the sinoatrial node) that were spontaneously beating after enzymatic isolation from rabbit hearts...
September 15, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28887333/rapid-estrogen-receptor-alpha-signaling-mediated-by-erk-activation-regulates-vascular-tone-in-male-and-ovary-intact-female-mice
#5
Seong Chul Kim, Austin C Boese, Matthew H Moore, Rea M Cleland, Lin Chang, Patrice Delafontaine, Ke-Jie Yin, Jean-Pyo Lee, Milton H Hamblin
Estrogen has been shown to affect vascular reactivity. Here, we assessed estrogen receptor-alpha (ERα) dependency of estrogenic effects on vasorelaxation via a rapid nongenomic pathway in both male and ovary-intact female mice. We compared the effect of a primary estrogen, 17 beta-estradiol (E2) or 4,4',4"-(4-propyl-[1H]pyrazole-1,3,5-triyl)tris-phenol (PPT) (selective ERα agonist). We found that E2 and PPT induced greater aortic relaxation in females than males, indicating ERα mediation, which is further validated by employing ERα antagonism...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28887332/the-cerebro-cardiovascular-response-to-periodic-squat-stand-maneuvers-in-healthy-subjects-a-time-domain-analysis
#6
Sam C Barnes, Naomi Ball, Victoria Joanna Haunton, Thompson G Robinson, Ronney B Panerai
BACKGROUND: Squat-stand maneuvers (SSMs) have been used to improve the coherence of transfer function analysis (TFA) estimates during the assessment of dynamic cerebral autoregulation (dCA). There is a need to understand the influence of peripheral changes resulting from SSMs on cerebral blood flow, which might confound estimates of dCA. METHODS: 29 healthy subjects underwent recordings at rest (5 min standing) and 15 SSMs (0.05Hz). Heart rate (3-lead ECG), end-tidal CO2 (capnography), blood pressure (Finometer), cerebral blood velocity (CBV, transcranial Doppler, MCA) and the angle of the thigh (tilt sensor) were measured continuously...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28887331/shock-and-lethality-with-anthrax-edema-toxin-in-rats-are-associated-with-reduced-arterial-responsiveness-to-phenylephrine-and-are-reversed-with-adefovir
#7
Dante Alexander Suffredini, Yan Li, Wanying Xu, Mahtab Moayeri, Stephen H Leppla, Yvonne Fitz, Xizhong Cui, Peter Q Eichacker
INTRODUCTION: Although edema (ETx) and lethal toxin (LTx) contribute to B. anthracis shock and lethality, mechanisms underlying their cardiovascular effects are unclear. We previously showed that ETx but not LTx inhibited phenylephrine stimulated contraction of aortic rings prepared from healthy rats and adefovir, a selective inhibitor of ETx cAMP production, blocked this effect. Here we examined arterial function in rats receiving 24h ETx or LTx infusions. METHODS AND RESULTS: Compared to controls, ETx reduced mean arterial pressure (MAP) and survival over 48h (p≤0...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28887330/age-and-strain-related-aberrant-ca-2-release-is-associated-with-sudden-cardiac-death-in-the-actc-e99k-mouse-model-of-hypertrophic-cardiomyopathy
#8
Christina Rowlands, Thomas Owen, Saheed Lawal, Shuangyi Cao, Samata Pandey, Hsiang-Yu Yang, Weihua Song, Ross Wilkinson, Anita Alvarez-Laviada, Katja Gehmlich, Steven Marston, Kenneth T MacLeod
Patients with hypertrophic cardiomyopathy (HCM), particularly young adults, can die from arrhythmia but the mechanism underlying abnormal rhythm formation remains unknown. C57Bl6 x CBA/Ca mice carrying a cardiac actin (ACTC) E99K (Glu99Lys) mutation reproduce many aspects of human HCM including increased myofilament Ca(2+) sensitivity and sudden death in a proportion (up to 40%) of young (28-40 day old) animals. We studied the hearts of transgenic (TG - ACTC E99K) mice and their non-transgenic (NTG) littermates when they were in their vulnerable period (28-40 days old) and when they were adult (8-12 weeks old)...
September 8, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842441/carotid-artery-stenosis-in-hypertensive-rats-impairs-dilatory-pathways-in-parenchymal-arterioles
#9
Nusrat Matin, Courtney Fisher, William F Jackson, Janice M Diaz-Otero, Anne M Dorrance
Hypertension is a leading risk factor for vascular cognitive impairment and is strongly associated with carotid artery stenosis. In normotensive rats, chronic cerebral hypoperfusion induced by bilateral common carotid artery stenosis (BCAS) leads to cognitive impairment that is associated with impaired endothelium-dependent dilation in parenchymal arterioles (PAs). The aim of this study was to assess the effects of BCAS on PA function and structure in stroke prone spontaneously hypertensive rats (SHRSP), a model of human essential hypertension...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842440/age-related-impairment-of-metabo-vascular-coupling-during-cortical-spreading-depolarization
#10
Stéphane Marinesco, Zoltán Ungvári, Veronica Galvan
Cortical spreading depolarizations (SDs) may lead to long-lasting alterations in cerebral blood flow (CBF), which contribute to neuronal dysfunction and hypoxic tissue injury. There is growing evidence to suggest that age-related structural and functional alterations of the neurovascular unit significantly increase both the incidence of SDs and aggravate their functional consequences. Recent studies suggest that metabolic signaling plays a major role in modulating cerebral blood flow responses evoked by SDs and provide critical evidence that aging considerably weakens metabovascular coupling with SD...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842439/hypertrophic-cardiomyopathy-mutation-in-cardiac-troponin-t-r95h-attenuates-length-dependent-activation-in-guinea-pig-cardiac-muscle-fibers
#11
Alexis V Mickelson, Murali Chandra
The central region of cardiac troponin T (TnT) is important for modulating the dynamics of muscle length-mediated crossbridge recruitment. Therefore, hypertrophic cardiomyopathy mutations in the central region may affect crossbridge recruitment dynamics to alter myofilament Ca(2+) sensitivity and length-dependent activation of cardiac myofilaments. Given the importance of the central region of TnT for cardiac contractile dynamics, we studied if the hypertrophic cardiomyopathy-linked mutaton (TnTR94H)-induced effects on contractile function would be differently modulated by sarcomere length (SL)...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842438/plastics-and-cardiovascular-health-phthalates-may-disrupt-heart-rate-variability-and-cardiovascular-reactivity
#12
Rafael Jaimes, Adam Swiercz, Meredith Sherman, Narine Muselimyan, Paul Marvar, Nikki Gillum Posnack
BACKGROUND: Plastics have revolutionized medical device technology, transformed hematological care, and facilitated modern cardiology procedures. Despite these advances, studies have shown that phthalate chemicals migrate out of plastic products, and that these chemicals are bioactive. Recent epidemiological and research studies suggest that phthalate exposure adversely affects cardiovascular function. OBJECTIVE: To assess the safety and biocompatibility of phthalate chemicals, and resolve the impact on cardiovascular and autonomic physiology...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842437/hypoxia-promotes-primitive-glycosaminoglycan-rich-extracellular-matrix-composition-in-developing-heart-valves
#13
Dorothy Amofa, Alexia Hulin, Yuji Nakada, Hesham A Sadek, Katherine E Yutzey
During postnatal heart valve development, glycosaminoglycan (GAG)-rich valve primordia transform into stratified valve leaflets composed of GAGs, fibrillar collagen, and elastin layers accompanied by decreased cell proliferation, as well as thinning and elongation. The neonatal period is characterized by the transition from a uterine environment to atmospheric oxygen, but the role of changing O2 levels in valve extracellular matrix (ECM) composition or morphogenesis are not well-characterized. Here, we show that tissue hypoxia decreases in mouse aortic valves in the days after birth, concomitant with ECM remodeling and cell cycle arrest of valve interstitial cells (VICs)...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28842436/ca-2-calmodulin-kinase-ii-dependent-regulation-of-atrial-myocyte-late-na-current-ca-2-cycling-and-excitability-a-mathematical-modeling-study
#14
Birce Onal, Daniel Gratz, Thomas J Hund
Atrial fibrillation (AF) affects more than 3 million people per year in the U.S., and is associated with high morbidity and mortality. Both electrical and structural remodeling contribute to AF, but the molecular pathways underlying AF pathogenesis are not well understood. Recently, a role for Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in regulation of persistent "late" sodium current (INa,L) has been identified. While INa,L inhibition is emerging as a potential antiarrhythmic strategy in AF patients, little is known about the mechanism linking INa,L to atrial arrhythmogenesis...
August 25, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822969/preconditioning-with-the-bkca-channel-activator-ns-1619-prevents-ischemia-reperfusion-induced-inflammation-and-mucosal-barrier-dysfunction-ros-and-ho-1
#15
Hongyan Dai, Meifang Wang, Parag N Patel, Theodore J Kalogeris, Yajun Liu, William Durante, Ronald J Korthuis
Activation of large conductance, calcium-activated potassium (BKCa) channels evokes cell survival programs that mitigate intestinal ischemia and reperfusion (I/R) inflammation and injury 24 hours later. The goal of the current study was to determine the role of reactive oxygen species (ROS) and heme oxygenase (HO)-1 in delayed acquisition of tolerance to I/R induced by pretreatment with the BKCa channel opener NS-1619. Superior mesentery arteries were occluded for 45 min followed by reperfusion for 70 min in wild type (WT) or HO-1 null (HO-1(-/-)) mice that were pretreated with NS-1619 or saline vehicle 24 hrs earlier...
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822968/mineralocorticoids-the-secret-of-muscle-reflex-dysfunction-in-hypertension
#16
Han-Jun Wang
Not Applicable.
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822967/temporal-dynamics-of-cardiac-hypertrophic-growth-in-response-to-pressure-overload
#17
Yuan Wang, Yuannyu Zhang, Guanqiao Ding, Herman May, Jian Xu, Thomas G Gillette, Hang Wang, Zhao V Wang
Hypertension is one of the most important risk factors of heart failure. In response to high blood pressure, the left ventricle manifests hypertrophic growth to ameliorate wall stress, which may progress into decompensation and trigger pathological cardiac remodeling. Despite the clinical importance, the temporal dynamics of pathological cardiac growth remains elusive. Here, we took advantage of the puromycin labeling approach to measure the relative rates of protein synthesis as a way to delineate the temporal regulation of cardiac hypertrophic growth...
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822966/inhibitory-actions-of-the-nrg-1-erbb4-pathway-in-macrophages-during-tissue-fibrosis-in-heart-skin-and-lung
#18
Zarha Vermeulen, Anne-Sophie Hervent, Lindsey Dugaucquier, Leni Vandekerckhove, Miche Rombouts, Matthias Beyens, Dorien M Schrijvers, Guido R Y De Meyer, Stuart Maudsley, Gilles W De Keulenaer, Vincent Fm Segers
The neuregulin-1 (NRG-1)/ErbB system is an endothelium-controlled paracrine system modulating cardiac performance and adaptation. Recent studies indicate that NRG-1 has anti-fibrotic effects in the left ventricle (LV), which were explained by direct actions on cardiac fibroblasts. However, the NRG-1/ErbB system also regulates the function of macrophages. In this study, we hypothesized that the anti-fibrotic effect of NRG-1 in the heart is at least partially mediated through inhibitory effects on macrophages...
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822965/diabetes-increases-the-susceptibility-to-acute-kidney-injury-after-myocardial-infarction-through-augmented-activation-of-renal-toll-like-receptors-in-rats
#19
Kouhei Ohno, Atsushi Kuno, Hiromichi Murase, Shingo Muratsubaki, Takayuki Miki, Masaya Tanno, Toshiyuki Yano, Satoko Ishikawa, Tomohisa Yamashita, Tetsuji Miura
Acute kidney injury (AKI) after acute myocardial infarction (MI) worsens the prognosis of MI patients. Although type 2 diabetes mellitus (DM) is a major risk factor of AKI after MI, the underlying mechanism remains unclear. Here, we examined roles of renal toll-like receptors (TLRs) in the impact of DM on AKI after MI. MI was induced by coronary artery ligation in OLETF, a rat DM model, and LETO, non-diabetic controls. Sham-operated rats served as no-MI controls. Renal mRNA levels of TLR2 and MyD88 were significantly higher in sham-operated OLETF than in sham-operated LETO, though levels of TLR1, TLR3, and TRL4 were similar...
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28822964/moderate-to-severe-obstructive-sleep-apnea-is-associated-with-telomere-lengthening
#20
Katarzyna Polonis, Virend K Somers, Christiane Becari, Naima Covassin, Phillip J Schulte, Brooke R Druliner, Ruth A Johnson, Krzysztof Narkiewicz, Lisa A Boardman, Prachi Singh
Obstructive sleep apnea (OSA) is associated with cardiometabolic diseases. Telomere shortening is linked to hypertension, diabetes mellitus, and cardiovascular diseases. Because these conditions are highly prevalent in OSA, we hypothesized that telomere length (TL) would be reduced in OSA patients. We identified 106 OSA and 104 non-OSA subjects who underwent polysomnography evaluation. Quantitative PCR was used to measure telomere length in genomic DNA isolated from peripheral blood samples. The association between OSA and TL was determined using unadjusted and adjusted linear models...
August 19, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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