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American Journal of Physiology. Heart and Circulatory Physiology

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https://www.readbyqxmd.com/read/28432060/toll-like-receptor-2-tlr2-dominance-over-tlr4-in-stressful-conditions-for-its-detrimental-role-in-the-heart
#1
Ashim K Bagchi, Gauri Akolkar, Soma Mandal, Prathapan Ayyappan, Xi Yang, Pawan K Singal
It has been suggested that toll-like receptor 4 (TLR4) promotes interleukin-10 (IL-10)-mediated cardiac cell survival while another receptor, TLR2, from the same family is detrimental. Here we examined the interactive role of these two innate signaling molecules under stressful conditions including interleukin-10 knockout (IL-10(-/-)) mice, global ischemia/reperfusion (I/R) injury in rat hearts and in-vitro shRNA experimental models in presence or absence of IL-10 (10ng/ml). Circulating and myocardial levels of tumor necrosis factor-α (TNF-α) as well as apoptosis and fibrosis were higher in IL-10(-/-) mice...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28432059/increased-amplitude-of-inward-rectifier-k-currents-with-advanced-age-in-smooth-muscle-cells-of-murine-superior-epigastric-arteries
#2
Sebastien Hayoz, Jessica Pettis, Vanessa Bradley, Steven S Segal, William F Jackson
Inward rectifier K(+) channels (KIR) may contribute to skeletal muscle blood flow regulation and adapt to advanced age. Using mouse abdominal wall superior epigastric arteries (SEAs) from either young (3-6 months) or old (24-26 months) male C57BL/6 mice, we investigated whether SEA smooth muscle cells (SMCs) express functional KIR, and how aging may affect KIR function. Freshly dissected SEAs were either enzymatically dissociated to isolate SMCs for electrophysiological recording (perforated patch) and mRNA expression, or used intact for pressure myography...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28432058/mk5-haplodefficiency-attenuates-hypertrophy-and-preserves-diastolic-function-during-remodeling-induced-by-chronic-pressure-overload-in-the-mouse-heart
#3
Sherin Nawaito, Dharmendra Dingar, Pramod Sahadevan, Bahira Hussein, Fatiha Sahmi, Yanfen Shi, Marc-Antoine Gillis, Matthias Gaestel, Jean-Claude Tardif, Bruce G Allen
MK5 is a protein serine and threonine kinase that is activated by p38 MAPK and the atypical MAPKs ERK3 and ERK4. The physiological function(s) of MK5 remain unknown. Herein we examine the effect of MK5 haplodeficiency on cardiac function and myocardial remodeling. At 12-weeks of age, MK5 haplodeficient mice (MK5(+/-)) were smaller than age-matched wild-type litter mates (MK5(+/+)), with similar diastolic function but reduced systolic function. Transverse aortic constriction (TAC) was employed to induce a chronic pressure overload in twelve-week-old male MK5(+/-) and MK5(+/+) mice...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28432057/imaging-and-modeling-of-acute-pressure-induced-changes-of-collagen-and-elastin-microarchitectures-in-pig-and-human-resistance-arteries
#4
Maria Bloksgaard, Thomas M Leurgans, Bart Spronck, Maarten Hg Heusinkveld, Bjarne Thorsted, Kristoffer Rosenstand, Inger Nissen, Ulla Melchior Hansen, Jonathan R Brewer, Luis A Bagatolli, Lars M Rasmussen, Akhmadjon Irmukhamedov, Koen D Reesink, Jo G R De Mey
The impact of disease related changes in the extracellular matrix (ECM) on the mechanical properties of human resistance arteries largely remains to be established. Resistance arteries from both pig and human parietal pericardium (PRA) display a different ECM microarchitecture compared to frequently used rodent mesenteric arteries. We hypothesized that the biaxial mechanics of PRA mirror pressure induced changes in the ECM microarchitecture. This was tested using isolated pig PRA as model system, integrating vital imaging, pressure myography and mathematical modeling...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28411233/vasculopathy-in-the-setting-of-cardiorenal-syndrome-the-roles-of-protein-bound-uremic-toxins
#5
Jingbin Guo, Lu Lu, Yue Hua, Kevin Huang, Ian Wang, Li Huang, Qiang Fu, Aihua Chen, Paul Chan, Huimin Fan, Zhong-Min Liu, Bing Hui Wang
Chronic kidney disease (CKD) often leads to and accelerates the progression of cardiovascular disease (CVD), whilst CVD also causes kidney dysfunction. This bidirectional interaction leads to the development of a complex syndrome known as cardiorenal syndrome (CRS). CRS not only involves both the heart and the kidney, but also the vascular system through a vast array of contributing factors. In addition to hemodynamic, neuro-hormonal, mechanical and biochemical factors, the non-dialyzable protein-bound uremic toxins (PBUTs) are also key contributing factors that have been demonstrated through in vitro, in vivo and clinical observations...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28411232/wnt5a-regulates-adipose-tissue-angiogenesis-via-anti-angiogenic-vegfa165b-in-obese-humans
#6
Shakun Karki, Doan Ngo, Melissa G Farb, Song-Young Park, Samantha M Saggese, Naomi M Hamburg, Brian Carmine, Donald T Hess, Kenneth Walsh, Noyan Gokce
Experimental studies suggest that Wingless-related integration site 5a (WNT5A) is a pro-inflammatory secreted protein that is associated with metabolic dysfunction in obesity. Impaired angiogenesis in fat has been implicated in the development of adipose tissue capillary rarefaction, hypoxia, inflammation and metabolic dysfunction. We recently demonstrated that impaired adipose tissue angiogenesis is associated with overexpression of anti-angiogenic factor VEGF-A165b in human fat and the systemic circulation...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28411231/angiotensin-1-7-attenuates-angiotensin-ii-induced-cardiac-hypertrophy-via-a-sirt3-dependent-mechanism
#7
Lirong Guo, Ankang Yin, Qi Zhang, Tiecheng Zhong, Stephen T O'Rourke, Chengwen Sun
The objectives of the current study were to investigate the effect of Ang-(1-7) on the development of cardiac hypertrophy, and to identify the intracellular mechanism underlying this action of Ang-(1-7). Blood pressure and heart rate were recorded using radiotelemetry before and after chronic subcutaneous infusion of control (PBS), Ang II, Ang-(1-7), or Ang II+Ang-(1-7) for 4 weeks in normotensive rats. Chronic administration of Ang-(1-7) did not affect either basal blood pressure or the Ang II-induced elevation in blood pressure...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28411230/interaction-of-12-15-lipoxygenase-with-fatty-acids-alters-the-leukocyte-kinetics-leading-to-improved-post-myocardial-infarction-healing
#8
Ganesh V Halade, Vasundhara Kain, Kevin A Ingle, Sumanth D Prabhu
The metabolic transformation of fatty acids to form oxylipids using 12/15lipoxygenase (LOX) can promote either resolving or non-resolving inflammation. However, the mechanism of how 12/15LOX interacts with PUFA (polyunsaturated fatty acids) in post-myocardial infarction (MI) healing is unclear. Here, we reported the role of 12/15LOX in post-MI cardiac remodeling in a PUFA (10% w/w, 22 Kcal) enriched environment. Wild-type (WT; C57BL/6J) and 12/15LOX null (12/15LOX(-/-)) male mice of 8-12-weeks age were fed PUFA-enriched diet for 1 month and subjected to permanent coronary artery ligation...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28411229/a-comprehensive-analysis-of-myocardial-substrate-preference-emphasizes-the-need-for-a-synchronized-fluxomic-metabolomic-research-design
#9
Mukundan Ragavan, Alexander Kirpich, Xiaorong Fu, Shawn C Burgess, Lauren M McIntyre, Matthew E Merritt
The heart oxidizes fatty acids, carbohydrates and ketone bodies inside the citric acid cycle (CAC) to generate the reducing equivalents needed for ATP production. Competition between these substrates makes it difficult to estimate the extent of pyruvate oxidation. Previously, hyperpolarized pyruvate detected propionate mediated activation of carbohydrate oxidation, even in the presence of acetate. In this report, the optimal concentration of propionate for activation of glucose oxidation is measured in mouse hearts perfused in Langendorff mode...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28389603/the-impact-of-ryr2-potentiation-on-myocardial-function
#10
Elena Lascano, Jorge A Negroni, Martin Vila Petroff, Alicia Mattiazzi
This perspective attempts to shed light on an old and not yet solved controversy in cardiac physiology, i.e. the impact of increasing RyR2 open probability on myocardial function. Based on an already proved myocyte model, it is shown that increasing RyR2 open probability results in a purely short-lived increase in Ca(2+) transient amplitude, and therefore it does not increase cardiac contractility. However, potentiation of RyR2 activity permanently enhances fractional Ca(2+) release, shifting the intracellular Ca(2+) transient vs SR Ca(2+) content curve to a new state of higher efficiency...
April 7, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28389602/shear-mediated-dilation-of-the-internal-carotid-artery-occurs-independent-of-hypercapnia
#11
Ryan L Hoiland, Kurt Jason Smith, Howard H Carter, Nia C S Lewis, Michael M Tymko, Kevin W Wildfong, Anthony R Bain, Daniel J Green, Philip N Ainslie
Evidence for shear stress as a regulator of carotid artery dilation in response to increased arterial carbon dioxide was recently demonstrated in humans during sustained elevations in CO2 (hypercapnia); however, the relative contributions of CO2 and shear stress to this response remains unclear. We examined the hypothesis that, following a 30-second transient increase in arterial CO2 tension and consequent increase in internal carotid artery shear stress, internal carotid artery diameter would increase, indicating shear-mediated dilation, in the absence of concurrent hypercapnia...
April 7, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28389601/anterior-cerebral-blood-velocity-and-end-tidal-co2-responses-to-exercise-differ-in-children-and-adults
#12
Lindsay A Ellis, Philip N Ainslie, Victoria A Armstrong, Laura Emily Morris, Ryan Gerard Simair, Nathan R Sletten, Christine M Tallon, Ali Mary McManus
Little is known about the response of the cerebrovasculature to acute exercise in children and how these responses might differ with adults. Therefore, we compared changes in middle cerebral artery blood velocity (MCAVmean), partial pressure of end-tidal carbon dioxide (PETCO2), blood pressure and ventilation (VE) in response to incremental exercise between children and adults. Thirteen children [aged 9±1 (SD) y] and 13 sex-matched adults [aged 25±4 y] completed a maximal exercise test during which MCAVmean, PETCO2 and VE were measured continuously...
April 7, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28364019/arterial-viscoelasticity-role-in-the-dependency-of-pulse-wave-velocity-on-heart-rate-in-conduit-arteries
#13
Hanguang Xiao, Isabella Tan, Mark Butlin, Decai Li, Alberto P Avolio
Experimental investigations have established that the stiffness of large arteries has a dependency on acute heart rate (HR) changes. However, possible underlying mechanisms inherent in this HR dependency have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multi-segment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the dependence of aortic arch to femoral artery pulse wave velocity (afPWV) on HR...
March 31, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28364018/ultrasound-detection-of-altered-placental-vascular-morphology-based-on-hemodynamic-pulse-wave-reflection
#14
Anum Rahman, Yu-Qing Zhou, Yohan Yee, Jun Dazai, Lindsay S Cahill, John C Kingdom, Chris Macgowan, John G Sled
Abnormally pulsatile umbilical artery (UA) Doppler ultrasound velocity waveforms are a hallmark of severe or early-onset placental-mediated intrauterine growth restriction (IUGR) while milder late-onset IUGR pregnancies typically have normal UA pulsatility. The diagnostic utility of these waveforms to detect placental pathology is thus limited, and hampered by factors outside of the placental circulation including fetal cardiac output. We developed a new ultrasound approach to isolate that portion of the UA Doppler waveform that originates from the placenta, specifically the reflected pulse pressure wave propagating backward along the UA...
March 31, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28364017/recording-sympathetic-nerve-activity-in-conscious-humans-and-other-mammals-guidelines-and-the-road-to-standardization
#15
Emma C J Hart, Geoffrey A Head, Jason R Carter, Gunnar Wallin, Clive N May, Shereen M Hamza, John E Hall, Nisha Charkoudian, John W Osborn
Over the past several decades, studies of the sympathetic nervous system in humans, sheep, rabbits, rats and mice have substantially increased mechanistic understanding of cardiovascular function and dysfunction. Recently, interest in sympathetic neural mechanisms contributing to blood pressure control has grown, due in part to the development of devices or surgical procedures, which treat hypertension by manipulating sympathetic outflow. Studies in animal models have provided important insights into physiological and pathophysiological mechanisms, which are not accessible in human studies...
March 31, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28364016/reduced-membrane-cholesterol-limits-pulmonary-endothelial-ca-2-entry-following-chronic-hypoxia
#16
Bojun Zhang, Jay S Naik, Nikki L Jernigan, Benjimen R Walker, Thomas C Resta
Chronic hypoxia (CH)-induced pulmonary hypertension is associated with diminished production of endothelium-derived Ca(2+)-dependent vasodilators such as nitric oxide. Interestingly, ATP-induced endothelial Ca(2+) entry as well as membrane cholesterol (Chol) are decreased in pulmonary arteries from CH rats (4 wk, PB = 380 Torr) compared to normoxic controls. Store-operated Ca(2+) entry (SOCE) and depolarization-induced Ca(2+) entry are major components of the response to ATP and are similarly decreased after CH...
March 31, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28341635/sept7b-is-required-for-the-subcellular-organization-of-cardiomyocytes-and-cardiac-function-in-zebrafish
#17
Surjya Narayan Dash, Suneeta Narumanchi, Jere Paavola, Sanni Perttunen, Hong Wang, Päivi Lakkisto, Ilkka Tikkanen, Sanna Lehtonen
Myofibrils made up of actin and myosin and associated proteins generate the contractile force in muscle and consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here we show that septin 7 is expressed in both embryonic and adult zebrafish heart, and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in the heart in embryonic and larval zebrafish...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28341634/contribution-of-two-pore-potassium-channels-to-cardiac-ventricular-action-potential-revealed-using-human-ipsc-derived-cardiomyocytes
#18
Sam Chai, Xiaoping Wan, Drew M Nassal, Haiyan Liu, Christine S Moravec, Angelina Ramirez-Navarro, Isabelle Deschenes
Two pore potassium channels (K2p) have been described in modulating background conductance as leak channels in different physiological systems. In the heart, the expression of K2p channels is heterogeneous with equivocation regarding their functional role. Our objective was to determine the K2p expression profile and their physiological and pathophysiological contribution to cardiac electrophysiology. Induced pluripotent stem cells (iPSC) cells generated from humans were differentiated into cardiomyocytes (iPSC-CM)...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28341633/increased-hypoxia-inducible-factor-in-the-muscles-of-tumor-bearing-mice
#19
Raymond Devine, Sabahattin Bicer, Peter J Reiser, Loren E Wold
Cancer cachexia is a progressive wasting disease resulting in significant effects on the quality of life and a high mortality. Most studies on cancer cachexia have focused on skeletal muscle; however, the heart is now recognized as a major site of cachexia-related effects. In order to elucidate possible mechanisms, a proteomic study was performed on the left ventricles of colon-26 adenocarcinoma tumor-bearing mice. The results revealed several changes in proteins involved in metabolism. An integrated pathway analysis of the results revealed a common mediator in hypoxia inducible factor-1α (HIF-1α)...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28341632/microvascular-leakage-in-acute-myocardial-infarction-characterization-by-histology-biochemistry-and-magnetic-resonance-imaging
#20
Xiao-Ming Gao, Qi-Zhu Wu, Helen Kiriazis, Yidan Su, Li-Ping Han, James Pearson, Andrew Taylor, Xiao-Jun Du
Cardiac microvascular obstruction (MVO) following ischemia/reperfusion (I/R) has been well studied, but microvascular leakage (MVL) remains largely unexplored. We characterized MVL in the mouse I/R model by histology, biochemistry and cardiac magnetic resonance (CMR) imaging. I/R was induced surgically in mice. MVL was determined by administrating microvascular permeability tracer Evans blue (EB) and/or gadolinium-DTPA contrast. The size of MVL, infarction and MVO in the heart was quantified histologically...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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