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American Journal of Physiology. Heart and Circulatory Physiology

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https://www.readbyqxmd.com/read/27881388/hyperglycemia-induces-defective-ca2-homeostasis-in-cardiomyocytes
#1
Andrea Sorrentino, Giulia Borghetti, Yu Zhou, Antonio Cannata, Marianna Meo, Sergio Signore, Piero Anversa, Annarosa Leri, Polina Goichberg, Khaled Qanud, Jason T Jacobson, Thomas H Hintze, Marcello Rota
Diabetes and other metabolic conditions characterized by elevated blood glucose constitute important risk factors for cardiovascular disease. Hyperglycemia targets myocardial cells rendering ineffective mechanical properties of the heart, but cellular alterations dictating the progressive deterioration of cardiac function with metabolic disorders remain to be clarified. In the current study, we examined the effects of hyperglycemia on cardiac function and myocyte physiology by employing mice with high blood glucose induced by administration of streptozotocin, a compound toxic to insulin-producing β-cells...
November 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27881387/intrauterine-growth-restriction-influences-vascular-remodeling-and-stiffening-in-the-weanling-rat-more-than-sex-or-diet
#2
R Blair Dodson, Thomas A Miller, Kyle N Powers, Yueqin Yang, Baifeng Yu, Kurt H Albertine, Erin K Zinkhan
Intrauterine growth restriction (IUGR) increases the incidence of adult cardiovascular disease (CVD). The sex-specific developmental mechanisms for IUGR-induced and western high fat diet (HFD) modification of CVD remain poorly understood. We hypothesized a maternal HFD in the Sprague-Dawley rat would augment IUGR-induced CVD in the offspring through decreased cardiac function and increased extracellular matrix (ECM) remodeling and stiffness in a sex-specific manner. HFD or regular diet (Reg) was given from 5 weeks prior to mating through postnatal day 21 (PND21)...
November 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27881386/ppar%C3%AE-augments-heart-function-and-cardiac-fatty-acid-oxidation-in-early-experimental-polymicrobial-sepsis
#3
Stephen Wade Standage, Brock G Bennion, Taft Olpin Knowles, Dolena R Ledee, Michael A Portman, John K McGuire, W Conrad Liles, Aaron K Olson
Children with sepsis and multisystem organ failure have downregulated leukocyte gene expression of PPARα, a nuclear hormone receptor transcription factor that regulates inflammation and lipid metabolism. Mouse models of sepsis have likewise demonstrated that the absence of PPARα is associated with decreased survival and organ injury, specifically of the heart. Using a clinically relevant mouse model of early sepsis, we found that heart function increases in wild type (WT) mice over the first 24 hours of sepsis, but that mice lacking PPARα (Ppara(-/-)) cannot sustain the elevated heart function necessary to compensate for sepsis pathophysiology...
November 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27881385/antihypertensive-effects-of-peroxisome-proliferator-activated-receptor-%C3%AE-%C3%AE-activation
#4
Marta Toral, Miguel Romero, Francisco Perez-Vizcaino, Juan Duarte, Rosario Jimenez
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors, which is composed of three members encoded by distinct genes: PPARα, PPARβ/δ, and PPARγ. The biological actions of PPARα and PPARγ and their potential as a cardiovascular therapeutic target have been extensively reviewed, whereas the biological actions of PPARβ/δ and its effectiveness as a therapeutic target in the treatment of hypertension remain less investigated...
November 23, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27864235/l5-ldl-from-st-elevation-myocardial-infarction-patients-induces-il-1%C3%AE-production-via-lox-1-and-nlrp3-inflammasome-activation-in-macrophages
#5
Tzu-Ching Yang, Po-Yuan Chang, Shao-Chun Lu
L5-LDL, the most electronegative LDL associated with major cardiovascular risks, significantly rises in patients with ST-segment elevation myocardial infarction (STEMI). The inflammatory nature of atherosclerotic vascular diseases has prompted us to investigate whether L5-LDL induces the production of inflammatory cytokines, especially vascular ischemia-related interleukin (IL)-1β in the pathogenesis of STEMI. Clinical data showed that plasma levels of L5-LDL and IL-1β were higher in the STEMI patients than in the controls (p < 0...
November 18, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27864234/interruption-of-perivascular-sympathetic-nerves-of-cerebral-arteries-offers-neuroprotection-against-ischemia
#6
Reggie Hui-Chao Lee, Alexandre Couto E Silva, Francesca M Lerner, Carl S Wilkins, Stephen E Valido, Daniel D Klein, Celeste Yin-Chieh Wu, Jake T Neumann, David Della-Morte, Stephen H Koslow, Alireza Minagar, Hung-Wen Lin
Sympathetic nervous system activity is increased after cardiopulmonary arrest, resulting in vasoconstrictor release from the perivascular sympathetic nerves of cerebral arteries. However, the pathophysiological function of the perivascular sympathetic nerves in the ischemic brain remains unclear. A rat model of global cerebral ischemia (asphyxial cardiac arrest, ACA) was utilized to investigate perivascular sympathetic nerves of cerebral arteries via bilateral decentralization (preganglionic lesion) of the superior cervical ganglion (SCG)...
November 18, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27864233/aging-is-associated-with-impaired-angiogenesis-but-normal-microvascular-network-structure-in-the-rat-mesentery
#7
Richard S Sweat, David C Sloas, Scott A Stewart, Malwina Czarny-Ratajczak, Melody Baddoo, James R Eastwood, Ariana D Suarez-Martinez, Mohammad Sadegh Azimi, Hope E Burks, Lee O Chedister, Leann Myers, Walter Lee Murfee
A big problem associated with aging is thought to be impaired microvascular growth or angiogenesis. However, in order to link the evidence for impaired angiogenesis to microvascular dysfunction in aged tissues, we must compare adult versus aged microvascular networks in unstimulated scenarios. The objective of this study was to test the hypothesis that aged microvascular networks are characterized by both fewer vessels and the impaired ability to undergo angiogenesis. Mesentery tissues from adult (9 months) and aged (24 months) male Fischer 344 rats were harvested and immunolabeled for PECAM (an endothelial cell marker) according to two scenarios: unstimulated and stimulated...
November 18, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27836897/positive-versus-negative-effects-of-vegf165-on-ca2-signaling-and-no-production-in-human-endothelial-cells
#8
Derek S Boeldt, Jennifer Krupp, Fu-Xian Yi, Nauman Khurshid, Dinesh M Shah, Ian M Bird
The role increased vascular endothelial growth factor (VEGF) plays in vascular function during normal vs preeclamptic pregnancy has been a source of some controversy of late. In this study we seek to understand how VEGF165 influences vasodilator production via Ca(2+) signaling mechanisms in human endothelial cells. We utilize human umbilical vein endothelial cells (HUVEC) as well as intact ex vivo human umbilical vein (HUV Endo) to address direct stimulation of Ca(2+) and NO by VEGF165 alone, as well as the effect of VEGF165 on subsequent ATP-stimulated Ca(2+) signaling and NO production...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27836896/reduced-nitric-oxide-bioavailability-mediates-cerebroarterial-dysfunction-independent-of-cerebral-amyloid-angiopathy-in-a-mouse-model-of-alzheimer-s-disease
#9
Mario Merlini, Yi Shi, Stephan Keller, Gianluigi Savarese, Alexander Akhmedov, Rebecca Derungs, Remo Daniel Spescha, Luka Kulic, Roger Nitsch, Thomas Lüscher, Giovanni Camici
In Alzheimer's disease (AD), cerebral arteries, in contrast to cerebral microvessels, show both cerebral amyloid angiopathy- (CAA) dependent and -independent vessel wall pathology. However, it remains unclear whether CAA-independent vessel wall pathology affects arterial function thereby chronically reducing cerebral perfusion, and if so which mechanisms mediate this effect. To this end, we assessed the ex vivo vascular function of the basilar artery and a similar-sized peripheral artery (femoral artery) in the Swedish-Arctic (SweArc) transgenic AD mouse model at different disease stages...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27836895/lifelong-quercetin-enrichment-and-cardioprotection-in-mdx-utrn-ice
#10
Christopher Ballmann, Thomas Denney, Ronald J Beyers, Tiffany S Quindry, Matthew Romero, Rajesh H Amin, Joshua T Selsby, John C Quindry
Duchenne Muscular Dystrophy (DMD) is associated with progressive cardiac pathology, however, the SIRT1/PGC1-α activator quercetin may cardioprotect dystrophic hearts. We tested the extent to which long term 0.2% dietary quercetin enrichment attenuates dystrophic cardiopathology in Mdx/Utrn(+/-) mice. At 2 months, Mdx/Utrn(+/-) mice were fed quercetin enriched (Mdx/Utrn(+/-)-Q) or control diet (Mdx/Utrn(+/-)) for 8 months. Control C57BL/10 (C57) animals were fed a control diet for 10 months. Cardiac function was quantified by MRI at 2 and 10 months...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27836894/acute-limb-heating-improves-macro-and-microvascular-dilator-function-in-the-leg-of-aged-humans
#11
Steven A Romero, Daniel Gagnon, Amy Adams, Matthew Cramer, Ken Kouda, Craig G Crandall
Local heating of an extremity increases blood flow and vascular shear stress throughout the arterial tree. Local heating acutely improves macrovascular dilator function in the upper limbs of young healthy adults through a shear stress dependent mechanism, but has no such effect in the lower limbs of this age group. The effect of acute limb heating on dilator function within the atherosclerotic prone vasculature of the lower limbs of aged adults is unknown. Therefore, the purpose of this study was to test the hypothesis that acute lower limb heating improves macro- and microvascular dilator function within the leg vasculature of aged adults...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27836893/dynamical-mechanisms-of-phase-2-early-afterdepolarizations-in-human-ventricular-myocytes-insights-from-bifurcation-analyses-of-two-mathematical-models
#12
Yasutaka Kurata, Kunichika Tsumoto, Kenshi Hayashi, Ichiro Hisatome, Mamoru Tanida, Yuhichi Kuda, Toshishige Shibamoto
Early afterdepolarization (EAD) is known as a cause of ventricular arrhythmias in long QT syndromes. We theoretically investigated how the rapid (IKr) and slow (IKs) components of delayed-rectifier K(+) channel currents, L-type Ca(2+) channel current (ICaL), Na(+)/Ca(2+) exchanger current (INCX), Na(+)-K(+) pump current (INaK), intracellular Ca(2+) (Cai) handling via sarcoplasmic reticulum (SR) and intracellular Na(+) concentration (Nai) contribute to initiation, termination and modulation of phase-2 EADs, using two human ventricular myocyte models...
November 11, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27815252/chymase-dependent-production-of-angiotensin-ii-an-old-enzyme-in-old-hearts
#13
Ghezal Froogh, John T Pinto, Yicong Le, Sharath Kandhi, Yeabsra Aleligne, An Huang, Dong Sun
Age-dependent alteration of the renin-angiotensin-system (RAS) and generation of angiotensin II (Ang II) are well documented. By contrast, RAS-independent generation of angiotensin II in aging and its responses to exercise have not been explored. To this end, we examined the effects of chymase, a secretory serine protease, on the angiotensin converting enzyme (ACE)-independent conversion of Ang I to Ang II. We hypothesize that age-dependent alteration of cardiac Ang II formation is chymase-dependent in nature and is prevented by exercise training...
November 4, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27793856/prediction-of-hemodynamics-under-left-ventricular-assist-device
#14
Takamori Kakino, Keita Saku, Takafumi Sakamoto, Kazuo Sakamoto, Takuya Akashi, Masataka Ikeda, Tomomi Ide, Takuya Kishi, Hiroyuki Tsutsui, Kenji Sunagawa
Left ventricular assist device (LVAD) saves lives in patients with severe left ventricular (LV) failure. However, predicting how much LVAD boosts total cardiac output (CO) remains difficult. This study aimed to develop a framework to quantitatively predict the impact of LVAD on hemodynamics. We adopted the circulatory equilibrium framework and incorporated LVAD into the integrated CO curve to derive the circulatory equilibrium. In anesthetized dogs, we ligated left coronary arteries to create LV failure and inserted a centrifugal pump as LVAD...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27793855/functional-vascular-contributions-to-cognitive-impairment-and-dementia-vcid-mechanisms-and-consequences-of-cerebral-microvascular-dysfunction-in-aging
#15
Peter Toth, Stefano Tarantini, Anna Csiszar, Zoltan I Ungvari
Increasing evidence from epidemiological, clinical and experimental studies indicate that age-related cerebromicrovascular dysfunction and microcirculatory damage play critical roles in the pathogenesis of many types of dementia in the elderly, including Alzheimer's disease. Understanding and targeting the age-related pathophysiological mechanisms that underlie vascular contributions to cognitive impairment and dementia (VCID) is expected to have a major role in preserving brain health in older individuals...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27793854/myocardial-interstitial-levels-of-serotonin-and-its-major-metabolite-5-hydroxyindole-acetic-acid-during-ischemia-reperfusion
#16
Cheng-Kun Du, Dong-Yun Zhan, Tsuyoshi Akiyama, Tadakatsu Inagaki, Toshiaki Shishido, Mikiyasu Shirai, James Todd Pearson
The aim of this study was to examine the accumulation of serotonin (5-HT) and degradation of 5-HT taken up into cells in the ischemic region during myocardial ischemia-reperfusion. Using microdialysis technique in anesthetized rats, we monitored myocardial interstitial levels of 5-HT and its metabolite produced by monoamine oxidase (MAO), 5-hydroxyindole acetic acid (5-HIAA), during 30-min coronary occlusion followed by 45-min reperfusion, and investigated the effects of local administration of the MAO inhibitor pargyline and the 5-HT uptake inhibitor fluoxetine...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27793853/investigating-the-extremes-of-the-continuum-of-paracrine-functions-in-cd34-cd31-cacs-across-diverse-populations
#17
Rian Q Landers-Ramos, Ryan M Sapp, Emily VandeWater, Jennifer Macko, Shawn Robinson, Yan Wang, Eva R Chin, Espen E Spangenburg, Steven J Prior, James M Hagberg
Paracrine function of circulating angiogenic cells (CACs) is thought to contribute to vascular maintenance. We previously identified S100A8 and S100A9 secreted from physically inactive individuals' CD34-/CD31+ CACs as negative regulators of capillary-like network formation. The purpose of this study was to further investigate the extremes of the continuum of CAC paracrine actions using two distinctly different groups representing "healthy" and "impaired" CAC function. We aimed to determine how capillary-like network formation in human umbilical vein endothelial cells (HUVECs) is affected by S100A8 and S100A9 in concentrations secreted by CACs from different ends of the health spectrum...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27793852/acute-exposure-to-progesterone-attenuates-cardiac-contraction-by-modifying-myofilament-calcium-sensitivity-in-the-female-mouse-heart
#18
Hirad A Feridooni, Jennifer K MacDonald, Anjali Ghimire, W Glen Pyle, Susan E Howlett
Acute application of progesterone attenuates cardiac contraction, although the underlying mechanisms are unclear. We investigated whether progesterone modified contraction in isolated ventricular myocytes and identified the Ca(2+) handling mechanisms involved in female C57BL/6 mice (6-9 mos; sodium pentobarbital anesthesia). Cells were field-stimulated (4 Hz; 37°C) and exposed to progesterone (0.001-10.0 μM) or vehicle (35 mins). Ca(2+) transients (fura-2) and cell shortening were recorded simultaneously...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27770000/left-and-right-ventricular-hemodynamic-forces-in-healthy-volunteers-and-elite-athletes-assessed-with-4d-flow-magnetic-resonance-imaging
#19
Per Martin Arvidsson, Johannes Töger, Marcus Carlsson, Katarina Steding-Ehrenborg, Gianni Pedrizzetti, Einar Heiberg, Hakan Arheden
Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only LV forces. Right ventricular forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify three-dimensional hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. 25 controls,14 elite endurance athletes, and two patients with left ventricular dyssynchrony were included...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27769999/cardiomyopathy-related-mutation-a30v-in-mouse-cardiac-troponin-t-divergently-alters-the-magnitude-of-stretch-activation-in-%C3%AE-and-%C3%AE-myosin-heavy-chain-fibers
#20
Alexis V Mickelson, Sampath K Gollapudi, Murali Chandra
The present study investigated the functional consequences of the human hypertrophic cardiomyopathy (HCM) mutation, A28V, in cardiac troponin T (TnT). The A28V mutation is located within the N-terminus of TnT, a region known to be important for full activation of cardiac thin filaments. The functional consequences of the A28V mutation in TnT remain unknown. Given how α- and β-myosin heavy chain (MHC) isoforms differently alter the effect of the N-terminus of TnT, we hypothesized that the A28V-induced effects would be differently modulated by α- and β-MHC isoforms...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
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