AJP: Heart and Circulatory Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Temperature-dependent modulation of regional lymphatic contraction frequency and flow
This study demonstrates to what extent lymphatic vessel intrinsic contractility and lymph flow are modulated by temperature and that this modulation is dependent on the body district that the vessels belong to, suggesting a possible functional misbehavior should lymphatic vessels be exposed to a chronically different temperature. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - November 1, 2017 Category: Cardiology Authors: Solari, E., Marcozzi, C., Negrini, D., Moriondo, A. Tags: RESEARCH ARTICLE Source Type: research

Impact of electrical defibrillation on infarct size and no-reflow in pigs subjected to myocardial ischemia-reperfusion without and with ischemic conditioning
Ventricular fibrillation (VF) occurs frequently during myocardial ischemia-reperfusion (I/R) and must then be terminated by electrical defibrillation. We have investigated the impact of VF/defibrillation on infarct size (IS) or area of no reflow (NR) without and with ischemic conditioning interventions. Anesthetized pigs were subjected to 60/180 min of coronary occlusion/reperfusion. VF, as identified from the ECG, was terminated by intrathoracic defibrillation. The area at risk (AAR), IS, and NR were determined by staining techniques (patent blue, triphenyltetrazolium chloride, and thioflavin-S). Four experimental protoco...
Source: AJP: Heart and Circulatory Physiology - November 1, 2017 Category: Cardiology Authors: Skyschally, A., Amanakis, G., Neuhäuser, M., Kleinbongard, P., Heusch, G. Tags: RESEARCH ARTICLE Source Type: research

A comparison of passive hindlimb cycling and active upper-limb exercise provides new insights into systolic dysfunction after spinal cord injury
In conclusion, PHLC improves flow-derived cardiac indexes, whereas SWIM training displayed no cardiobeneficial effect. Pressure-derived deficits were corrected only with dobutamine, suggesting that reduced β-adrenergic stimulation is principally responsible for the impaired cardiac contractile function after SCI. NEW & NOTEWORTHY This is the first direct comparison between the cardiac changes elicited by active upper-limb or passive lower-limb exercise after spinal cord injury. Here, we demonstrate that lower-limb exercise positively influences flow-derived cardiac indexes, whereas upper-limb exercise does not. Fu...
Source: AJP: Heart and Circulatory Physiology - November 1, 2017 Category: Cardiology Authors: DeVeau, K. M., Harman, K. A., Squair, J. W., Krassioukov, A. V., Magnuson, D. S. K., West, C. R. Tags: RESEARCH ARTICLE Source Type: research

Muscle contraction induced arterial shear stress increases endothelial nitric oxide synthase phosphorylation in humans
We determined if local increases in brachial artery shear during repetitive muscle contractions induce changes in protein expression of endothelial nitric oxide synthase (eNOS) and/or phosphorylated (p-)eNOS at Ser1177, the primary activation site on eNOS, in endothelial cells (ECs) of humans. Seven young male subjects (25 ± 1 yr) performed 20 separate bouts (3 min each) of rhythmic forearm exercise at 20% of maximum over a 2-h period. Each bout of exercise was separated by 3 min of rest. An additional six male subjects (24 ± 1 yr) served as time controls (no exercise). ECs were freshly isolated from the brac...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Casey, D. P., Ueda, K., Wegman-Points, L., Pierce, G. L. Tags: RAPID REPORT Source Type: research

Modulation of mesenteric collecting lymphatic contractions by {sigma}1-receptor activation and nitric oxide production
Recently, it has been reported that a -receptor antagonist could reduce inflammation-induced edema. Lymphatic vessels play an essential role in removing excess interstitial fluid. We tested the hypothesis that activation of -receptors would reduce or weaken collecting lymphatic contractions. We used isolated, cannulated rat mesenteric collecting lymphatic vessels to study contractions in response to the -receptor agonist afobazole in the absence and presence of different -receptor antagonists. We used RT-PCR and Western blot analysis to investigate whether these vessels express the 1-receptor and immunofluorescence confoca...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Trujillo, A. N., Katnik, C., Cuevas, J., Cha, B. J., Taylor-Clark, T. E., Breslin, J. W. Tags: RESEARCH ARTICLE Source Type: research

Enhanced NO-dependent pulmonary vasodilation limits increased vasoconstrictor sensitivity in neonatal chronic hypoxia
Augmented vasoconstrictor reactivity is thought to play an important role in the development of chronic hypoxia (CH)-induced neonatal pulmonary hypertension. However, whether this response to CH results from pulmonary endothelial dysfunction and reduced nitric oxide (NO)-mediated vasodilation is not well understood. We hypothesized that neonatal CH enhances basal tone and pulmonary vasoconstrictor sensitivity by limiting NO-dependent pulmonary vasodilation. To test this hypothesis, we assessed the effects of the NO synthase (NOS) inhibitor N-nitro-l-arginine (l-NNA) on baseline pulmonary vascular resistance (PVR) and vasoc...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Sheak, J. R., Weise-Cross, L., deKay, R. J., Walker, B. R., Jernigan, N. L., Resta, T. C. Tags: RESEARCH ARTICLE Source Type: research

Gq-activated fibroblasts induce cardiomyocyte action potential prolongation and automaticity in a three-dimensional microtissue environment
In conclusion, our data demonstrate that CF activation alone is capable of altering action potential and Ca2+ transient characteristics of CMs, leading to proarrhythmic electrical activity. Our results also emphasize the importance of a 3-D environment where cell-cell interactions are prevalent, underscoring that CF activation in 3-D tissue plays a significant role in modulating CM electrophysiology and arrhythmias. NEW & NOTEWORTHY In a three-dimensional microtissue model, which lowers baseline activation of cardiac fibroblasts but enables cell-cell, paracrine, and cell-extracellular matrix interactions, we demonstrat...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Kofron, C. M., Kim, T. Y., King, M. E., Xie, A., Feng, F., Park, E., Qu, Z., Choi, B.- R., Mende, U. Tags: RESEARCH ARTICLE Source Type: research

Vitamin C mitigates oxidative/nitrosative stress and inflammation in doxorubicin-induced cardiomyopathy
Increase in oxidative/nitrosative stress is one of the mechanisms associated with the development of cardiotoxicity due to doxorubicin (Dox), a potent chemotherapy drug. Previously, we reported mitigation of Dox-induced oxidative/nitrosative stress and apoptosis by vitamin C (Vit C) in isolated cardiomyocytes. In the present in vivo study in rats, we investigated the effect of prophylactic treatment with Vit C on Dox-induced apoptosis, inflammation, oxidative/nitrosative stress, cardiac dysfunction, and Vit C transporter proteins. Dox (cumulative dose: 15 mg/kg) in rats reduced systolic and diastolic cardiac function and c...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Akolkar, G., da Silva Dias, D., Ayyappan, P., Bagchi, A. K., Jassal, D. S., Salemi, V. M. C., Irigoyen, M. C., De Angelis, K., Singal, P. K. Tags: RESEARCH ARTICLE Source Type: research

Mineralocorticoid receptor antagonists attenuate exaggerated exercise pressor reflex responses in hypertensive rats
Exaggerated heart rate (HR) and blood pressure responses to exercise in hypertension are mediated, in part, by overactivity of the exercise pressor reflex (EPR). The mechanisms underlying this EPR dysfunction have not been fully elucidated. Previous studies have shown that stimulation of mineralocorticoid receptors (MRs) with exogenous administration of aldosterone in normal, healthy rats reproduces the EPR overactivity characteristic of hypertensive animals. Conversely, the purpose of this study was to examine whether antagonizing MR with spironolactone (SPIR) or eplerenone (EPL) in decerebrated hypertensive rats ameliora...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Downey, R. M., Mizuno, M., Mitchell, J. H., Vongpatanasin, W., Smith, S. A. Tags: RESEARCH ARTICLE Source Type: research

Muscle sympathetic nerve activity and volume-regulating factors in healthy pregnant and nonpregnant women
Healthy, normotensive human pregnancies are associated with striking increases in both plasma volume and vascular sympathetic nerve activity (SNA). In nonpregnant humans, volume-regulatory factors including plasma osmolality, vasopressin, and the renin-angiotensin-aldosterone system have important modulatory effects on control of sympathetic outflow. We hypothesized that pregnancy would be associated with changes in the relationships between SNA (measured as muscle SNA) and volume-regulating factors, including plasma osmolality, plasma renin activity, and arginine vasopressin (AVP). We studied 46 healthy, normotensive youn...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Charkoudian, N., Usselman, C. W., Skow, R. J., Staab, J. S., Julian, C. G., Stickland, M. K., Chari, R. S., Khurana, R., Davidge, S. T., Davenport, M. H., Steinback, C. D. Tags: RESEARCH ARTICLE Source Type: research

Circulating acylcarnitine profile in human heart failure: a surrogate of fatty acid metabolic dysregulation in mitochondria and beyond
This study aimed at testing the hypothesis that HF patients with reduced ejection fraction display systemic perturbations in levels of energy-related metabolites, especially those reflecting dysregulation of FA metabolism, namely, acylcarnitines (ACs). Circulating metabolites were assessed using mass spectrometry (MS)-based methods in two cohorts. The main cohort consisted of 72 control subjects and 68 HF patients exhibiting depressed left ventricular ejection fraction (25.9 ± 6.9%) and mostly of ischemic etiology with ≥2 comorbidities. HF patients displayed marginal changes in plasma levels of tricarboxylic acid...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Ruiz, M., Labarthe, F., Fortier, A., Bouchard, B., Thompson Legault, J., Bolduc, V., Rigal, O., Chen, J., Ducharme, A., Crawford, P. A., Tardif, J.-C., Des Rosiers, C. Tags: RESEARCH ARTICLE Source Type: research

Mitochondrial function in engineered cardiac tissues is regulated by extracellular matrix elasticity and tissue alignment
Mitochondria in cardiac myocytes are critical for generating ATP to meet the high metabolic demands associated with sarcomere shortening. Distinct remodeling of mitochondrial structure and function occur in cardiac myocytes in both developmental and pathological settings. However, the factors that underlie these changes are poorly understood. Because remodeling of tissue architecture and extracellular matrix (ECM) elasticity are also hallmarks of ventricular development and disease, we hypothesize that these environmental factors regulate mitochondrial function in cardiac myocytes. To test this, we developed a new procedur...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Lyra-Leite, D. M., Andres, A. M., Petersen, A. P., Ariyasinghe, N. R., Cho, N., Lee, J. A., Gottlieb, R. A., McCain, M. L. Tags: RESEARCH ARTICLE Source Type: research

TNF-{alpha} receptor 1 knockdown in the subfornical organ ameliorates sympathetic excitation and cardiac hemodynamics in heart failure rats
In systolic heart failure (HF), circulating proinflammatory cytokines upregulate inflammation and renin-angiotensin system (RAS) activity in cardiovascular regions of the brain, contributing to sympathetic excitation and cardiac dysfunction. Important among these is the subfornical organ (SFO), a forebrain circumventricular organ that lacks an effective blood-brain barrier and senses circulating humors. We hypothesized that the tumor necrosis factor-α (TNF-α) receptor 1 (TNFR1) in the SFO contributes to sympathetic excitation and cardiac dysfunction in HF rats. Rats received SFO microinjections of a TNFR1 shRNA...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Yu, Y., Wei, S.-G., Weiss, R. M., Felder, R. B. Tags: RESEARCH ARTICLE Source Type: research

Analysis of decreases in systemic arterial pressure and heart rate in response to the hydrogen sulfide donor sodium sulfide
The objective of the present study was to investigate the effect of H2S on the electrocardiogram and examine the relationship between H2S-induced changes in heart rate (HR), mean arterial pressure (MAP), and respiratory function. Intravenous administration of the H2S donor Na2S in the anesthetized Sprague-Dawley rat decreased MAP and HR and produced changes in respiratory function. The administration of Na2S significantly increased the RR interval at some doses but had no effect on PR or corrected QT(n)-B intervals. In experiments where respiration was maintained with a mechanical ventilator, we observed that Na2S-induced ...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Swan, K. W., Song, B. M., Chen, A. L., Chen, T. J., Chan, R. A., Guidry, B. T., Katakam, P. V. G., Kerut, E. K., Giles, T. D., Kadowitz, P. J. Tags: RESEARCH ARTICLE Source Type: research

Circumventing a broken heart: cytokines and the subfornical organ
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Yao, S. T., McKinley, M. J., May, C. N. Tags: EDITORIAL FOCUS Source Type: research