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    9961 results match your criteria American Journal of Physiology - Heart and Circulatory Physiology[Journal]

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    Novel role of PKR in palmitate-induced Sirt1 inactivation and endothelial cell senescence.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Department of Surgery, University of Pittsburgh School of Medicine, University of Pittsburgh School of Medicine, United States.
    Endothelial cell senescence is regarded as a vital characteristic of cardiovascular diseases (CVDs). Elevated palmitate (PA) is an independent risk factor of CVDs, but its role in the endothelial cell senescence is currently unknown. During the course of studying pro-senescent role of PA, we discovered a key role of double-stranded RNA-dependent protein kinase PKR in endothelial senescence. Read More

    Role of endothelial microRNA-23 clusters in angiogenesis in vivo.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Waseda University, Japan.
    The capillary network is distributed throughout the body, and its reconstruction is induced under various pathophysiological conditions. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression via post-transcriptional mechanisms and are involved in many biological functions including angiogenesis. Previous studies have shown that each miRNA of the miR-23 cluster, composed of the miR-23a cluster (miR-23a~27a~24-2) and miR-23b cluster (miR-23b~27b~24-2), regulates angiogenesis in vitro. Read More

    Engineering Cardiac Microphysiological Systems to Model Pathological Extracellular Matrix Remodeling.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Biomedical Engineering, University of Southern California, United States.
    Many cardiovascular diseases are associated with pathological remodeling of the extracellular matrix (ECM) in the myocardium. ECM remodeling is a complex, multi-factorial process that often contributes to declines in myocardial function and progression towards heart failure. However, the direct effects of the many forms of ECM remodeling on myocardial cell and tissue function remain elusive, in part because conventional model systems used to investigate these relationships lack robust experimental control over the ECM. Read More

    Changes in Cardiac Resident Fibroblast Physiology and Phenotype in Aging.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Medicine/Cardiovascular Sciences, Baylor College of Medicine, United States.
    The cardiac fibroblast plays a central role in tissue homeostasis and in repair after injury. With aging, dysregulated cardiac fibroblasts have a reduced capacity to respond to transforming growth factor-β (TGF-β) and poorly differentiate into contractile myofibroblasts. That results in the formation of an insufficient scar after myocardial infarction (MI). Read More

    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Yale School of Medicine, Department of Obstetrics, Gynecology and Reproductive and School of Public Health, The John B. Pierce Laboratory, United States.
    Hypertension, obesity, and endothelial function predict cardiovascular disease in women and these factors are interrelated. We hypothesized that hypertension and obesity are associated with endothelial dysfunction in young women, and that short-term ethinyl estradiol exposure mitigates this dysfunction. We examined flow-mediated dilation responses before and during 7 days of oral ethinyl estradiol (30 µg/day) in 19 women (25 {plus minus} 5, 18-35 yrs). Read More

    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Systems Biology & Translational Medicine, Texas A&M Health Science Center, United States.
    Current research indicates that vasomotor responses are altered with aging in skeletal muscle resistance arteries. The changes in vasomotor function are characterized by impaired vasodilator and vasoconstrictor responses. The detrimental effects of aging on vasomotor function are attenuated in some vascular beds following a program of endurance exercise training. Read More

    Scleraxis regulates Twist1 and Snai1 expression in epithelial-to-mesenchymal transition.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Physiology and Pathophysiology, University of Manitoba, Canada.
    Numerous physiological and pathological events, from organ development to cancer and fibrosis, are characterized by Epithelial-to-Mesenchymal Transition (EMT), whereby adherent epithelial cells convert to migratory mesenchymal cells. During cardiac development, pro-epicardial organ epithelial cells undergo EMT to generate fibroblasts. Subsequent stress or damage induces further phenotype conversion of fibroblasts to myofibroblasts, causing fibrosis via synthesis of excessive extracellular matrix. Read More

    High salt intake shifts the mechanisms of flow-induced dilation in the middle cerebral arteries of Sprague-Dawley rats.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Dept of Physiology and Immunology, Faculty of Medicine Josip Juraj Strossmayer University of Osijek, Croatia.
    The goal of this study was to examine the effect of 1-week of high salt (HS) intake and the role of oxidative stress in changing the mechanisms of flow-induced dilation (FID) in isolated pressurized middle cerebral arteries (MCA) of male Sprague-Dawley rats (N=15-16/per group). Reduced FID in the HS group was restored by intake of the superoxide scavenger TEMPOL (HS+TEMPOL in vivo group). Nitric oxide synthases (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME), COX inhibitor indomethacin (INDO) and selective inhibitor of microsomal CYP450 epoxidase activity N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MS-PPOH) significantly reduced FID in the LS group, while FID in the HS group was mediated by NO only. Read More

    New mouse model of pulmonary hypertension induced by respiratory syncytial virus bronchiolitis.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Louisiana State University, United States.
    Pulmonary hypertension (PH) has been observed in up to 75% of infants with moderate to severe respiratory syncytial virus (RSV) bronchiolitis and is associated with significant morbidity and mortality in infants with congenital heart disease. The purpose of this study was to establish a mouse model of PH secondary to RSV bronchiolitis that mimics the disease etiology as it occurs in infants. Neonatal mice were infected with RSV at 5 days of age, and then re-infected 4 weeks later. Read More

    Analysis of the microRNA signature driving adaptive right ventricular hypertrophy in an ovine model of congenital heart disease.
    Am J Physiol Heart Circ Physiol 2018 Jun 15. Epub 2018 Jun 15.
    Pediatrics, University of California, San Francisco, United States.
    The right ventricular (RV) response to pulmonary arterial hypertension (PAH) is heterogeneous. Most patients have maladaptive changes with RV dilation and failure while some-especially patients with PAH secondary to congenital heart disease (CHD)-have an adaptive response with hypertrophy and preserved systolic function. Mechanisms for RV adaptation to PAH are unknown despite RV function being a primary determinant of mortality. Read More

    No-reflow Phenomenon in Heart and Brain.
    Am J Physiol Heart Circ Physiol 2018 Jun 8. Epub 2018 Jun 8.
    Huntington Medical Research Institute, United States.
    The no-reflow phenomenon refers to the observation that when an organ is made ischemic by occlusion of a large artery supplying it, restoration of patency in that artery does not restore perfusion to the microvasculature supplying the parenchyma of that organ. This has been observed following prolonged arterial occlusions in the heart (30 to 90 minutes), brain, skin, and kidney. In experimental models, zones of no-reflow in the heart are characterized by ultrastructural microvascular damage, including focal endothelial swelling obstructing the lumen of small vessels. Read More

    Multi-scale Structure-Function Relationships in Right Ventricular Failure Due to Pressure Overload.
    Am J Physiol Heart Circ Physiol 2018 Jun 8. Epub 2018 Jun 8.
    Biomedical Engineering, University of Wisconsin, United States.
    Right ventricular failure (RVF) is the major cause of death in pulmonary hypertension. Recent studies have characterized changes in RV structure in RVF, including hypertrophy, fibrosis and abnormalities in mitochondria. Few if any studies have explored the relationships between these multi-scale structural changes and functional changes in RVF. Read More

    The influence of vagal control on sex-related differences in left ventricular mechanics and hemodynamics.
    Am J Physiol Heart Circ Physiol 2018 Jun 1. Epub 2018 Jun 1.
    School of Health and Exercise Sciences, University of British Columbia, Canada.
    Background: Left ventricular (LV) twist mechanics differ between males and females during acute physiological stress, which may be partly mediated by sex differences in autonomic control. While males appear to have greater adrenergic control of LV twist, the potential contribution of vagal modulation to sex differences in LV twist remains unknown. Therefore, this study examined the role of vagal control on sex differences in LV twist during graded lower body negative pressure (LBNP) and supine cycling. Read More

    High-intensity resistance exercise with low repetitions maintains endothelial function.
    Am J Physiol Heart Circ Physiol 2018 Jun 1. Epub 2018 Jun 1.
    Faculty of Bioscience and Applied Chemistry, Hosei University, Japan.
    Resistance exercise impairs endothelial function, and this impairment is thought to be mediated by sustained elevation in blood pressure. Herein, we tested the hypothesis that resistance exercise-induced endothelial dysfunction would be prevented by high-intensity resistance exercise with low repetitions. This type of resistance exercise is known to induce temporal elevation in blood pressure due to low repetitions and long resting period between sets. Read More

    Pressure-volume analysis reveals characteristic sex-related differences in cardiac function in a rat model of aortic banding-induced myocardial hypertrophy.
    Am J Physiol Heart Circ Physiol 2018 May 25. Epub 2018 May 25.
    Cardiac Surgery, University of Heidelberg.
    Sex differences in pressure overload (PO)-induced left ventricular (LV) myocardial hypertrophy (LVH) have been intensely investigated. Nevertheless, sex-related disparities of LV hemodynamics in LVH were not examined in detail. Therefore, we aimed to provide a detailed characterization of distinct aspects of LV function in male and female rats during different stages of LVH. Read More

    Biomechanical Relevance of the Microstructure in Artery Walls with a Focus on Passive and Active Components.
    Am J Physiol Heart Circ Physiol 2018 May 25. Epub 2018 May 25.
    School of Mathematics and Statistics, University of Glasgow.
    The microstructure of arteries, consisting, in particular, of collagen, elastin and vascular smooth muscle cells, plays a very significant role in their biomechanical response during a cardiac cycle. In this paper we highlight the microstructure and the contributions of each of its components to the overall mechanical behavior. We also describe the changes of the microstructure which occur as a result of abdominal aortic aneurysms and disease such as atherosclerosis. Read More

    Exercise cardiac MRI unmasks right ventricular dysfunction in acute hypoxia and chronic pulmonary arterial hypertension.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Cardiology, Imperial College London, United Kingdom.
    Background - Coupling of right ventricular (RV) contractility to afterload is maintained at rest in the early stages of pulmonary arterial hypertension (PAH), but exercise may unmask depleted contractile reserves. We assessed whether elevated afterload reduces RV contractile reserve despite compensated resting function using non-invasive exercise imaging. Methods and Results - Fourteen patients with PAH (mean age 39. Read More

    Venoarterial Communication Mediates Arterial Wall Shear Stress-Induced Maternal Uterine Vascular Remodeling During Pregnancy.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Obstetrics, Gynecology, and Reproductive Sciences, The University of Vermont.
    Although expansive remodeling of the maternal uterine circulation during pregnancy is essential for maintaining uteroplacental perfusion and normal fetal growth, the underlying physiological mechanisms are not well understood. Using a rat model, surgical approaches were used to alter uterine hemodynamics and wall shear stress (WSS) in order to evaluate the effects of WSS and venoarterial communication (e.g. Read More

    Human cerebral collateral arteriole function in normal cognition, mild cognitive impairment and dementia subjects.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Phoenix VA Medical Center.
    Clinical and preclinical studies suggest a link between cardiovascular disease and dementia disorders but the role of collateral brain circulation in cognitive dysfunction remains unknown. We aim to test the hypothesis that leptomeningeal arteriole (LMA) function and response to metabolic stressors differ among dementia, mild cognitive impairment (MCI) and normal cognition (CN) subjects. Following rapid autopsy, LMA were isolated from CN (N=10), MCI (N=12) or dementia subjects (N=42, Alzheimer's disease [AD], vascular dementia [VaD], or Other Dementia) and endothelial and smooth muscle-dependent function were measured at baseline and following exposure to β-amyloid (Aβ42 2 μM), palmitic acid (PA 150 μM) or medin (5μM) and compared. Read More

    Inhibitor of lysyl oxidase improves cardiac function and the collagen/MMP profile in response to volume overload.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Physiology, Louisiana State University Health Sciences Center, United States.
    The cardiac extracellular matrix is a complex architectural network that serves many functions including providing structural and biochemical support to surrounding cells, and regulating intercellular signaling pathways. Cardiac function is directly affected by extracellular matrix (ECM) composition, and alterations of the ECM contribute to progression of heart failure. Initially, collagen deposition is an adaptive response that aims to preserve tissue integrity and maintain normal ventricular function. Read More

    Humanin Analogue (HNG) Enhances the Protective Effect of Dexrazoxane against Doxorubicin-induced Cardiotoxicity.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Director, General Clinical Research Center, Harbor-UCLA Medical Center, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, United States.
    The chemotherapeutic effect of Doxorubicin (Dox) is limited by cumulative dose-dependent cardiotoxicity in cancer survivors. Dexrazoxane (DRZ) is approved to prevent Dox-induced cardiotoxicity. Humanin and its synthetic analog HNG have cytoprotective effect on the heart. Read More

    Apelin and APJ orchestrate complex tissue-specific control of cardiomyocyte hypertrophy and contractility in the hypertrophy-heart failure transition.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Cardiovascular Medicine, Stanford University, United States.
    The G protein coupled receptor APJ is a promising therapeutic target for heart failure. Constitutive deletion of APJ in the mouse is protective against the hypertrophy-heart failure transition via elimination of ligand-independent, β-arrestin dependent stretch transduction. However, the cellular origin of this stretch transduction and the details of its interaction with apelin signaling remain unknown. Read More

    Transactivation domain of p53 regulates DNA repair and integrity in human iPS cells.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    BME and Medicine, UAB, United States.
    The role of p53 transactivation domain (p53-TAD), a multifunctional and dynamic domain, on DNA repair and retaining DNA integrity in human iPS cells has never been studied. p53-TAD was knocked out in iPS cells using CRISPR/Cas9 and was confirmed by DNA sequencing. p53-TAD KO cells were characterized by: accelerated proliferation, decreased population doubling time, and unaltered Bcl2, BBC3, IGF1R, Bax and altered Mdm2, p21, and PIDD transcripts expression. Read More

    Lack of Tone in Mouse Small Mesenteric Arteries Leads to Outward Remodeling, which can be Prevented by Prolonged Agonist-Induced Vasoconstriction.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Dept. of Biomedical Sciences, University of Copenhagen, Denmark.
    Inward remodeling of resistance vessels is an independent risk factor for cardiovascular events. Thus far, the remodeling process remains incompletely elucidated, but the activation level of the vascular smooth muscle cell (VSMC) appears to play a central role. Accordingly, previous data suggest that an antagonistic and, supposedly beneficial, response - outward remodeling - may follow prolonged vasodilatation. Read More

    Effect of Healthy Aging and Sex on Middle Cerebral Artery Blood Velocity Dynamics During Moderate Intensity Exercise.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Physical Therapy and Rehabilitation Science, University of Kansas Medical Center, United States.
    Cerebral blood flow (CBF) velocity measured in the middle cerebral artery (MCA) increases with finite kinetics during moderate intensity exercise and both the amplitude and dynamics of the response provide invaluable insights into the controlling mechanisms. The MCA response following exercise onset is well fit to an exponential model in young individuals but remains to be characterized in their older counterparts. The responsiveness of vasomotor control degrades with advancing age, especially in skeletal muscle, and we tested the hypothesis that older subjects would evince a slower and reduced MCA response to exercise. Read More

    Phrase Mining of Textual Data to Analyze Extracellular Matrix Protein Patterns Across Cardiovascular Disease.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Computer Science, University of Illinois at Urbana Champaign.
    Extracellular matrix (ECM) proteins have been shown to play important roles regulating multiple biological processes in an array of organ systems, including the cardiovascular system. By using a novel bioinformatics text-mining tool, we studied six categories of cardiovascular disease (CVD), namely ischemic heart disease (IHD), cardiomyopathies (CM), cerebrovascular accident (CVA), congenital heart disease (CHD), arrhythmias (ARR), and valve disease (VD), anticipating novel ECM protein-disease and protein-protein relationships hidden within vast quantities of textual data. We conducted a phrase-mining analysis, delineating the relationships of 709 ECM proteins with the six groups of CVDs reported in 1,099,254 abstracts. Read More

    The Mouse Heart Attack Research Tool (mHART) 1.0 Database.
    Am J Physiol Heart Circ Physiol 2018 May 18. Epub 2018 May 18.
    Physiology and Biophysics, University of Mississippi Medical Center, United States.
    The generation of Big Data has enabled systems-level dissections into the mechanisms of cardiovascular pathology. Integration of genetic, proteomic, and pathophysiological variables across platforms and laboratories fosters discoveries through multidisciplinary investigations and minimizes unnecessary redundancy in research efforts. The Mouse Heart Attack Research Tool (mHART) consolidates a large dataset of over 10 years of experiments from a single laboratory for cardiovascular investigators to generate novel hypotheses and identify new predictive markers of progressive left ventricular remodeling following myocardial infarction (MI) in mice. Read More

    Cellular senescence links aging and diabetes in cardiovascular disease.
    Am J Physiol Heart Circ Physiol 2018 May 11. Epub 2018 May 11.
    University of Antwerp, Belgium.
    Aging is a powerful independent risk factor for cardiovascular diseases such as atherosclerosis and heart failure. Concomitant diabetes mellitus strongly reinforces this effect of aging on cardiovascular disease. Cellular senescence is a fundamental mechanism of aging and appears to play a crucial role in the onset and prognosis of cardiovascular disease in the context of both aging and diabetes. Read More

    Advanced age results in a diminished endothelial glycocalyx.
    Am J Physiol Heart Circ Physiol 2018 May 11. Epub 2018 May 11.
    Division of Geriatrics, University of Utah, United States.
    Age-related microvascular dysfunction is well characterized in rodents and humans, but little is known about the properties of the microvascular endothelial glycocalyx in advanced age. We examined the glycocalyx in microvessels of young and old C57BL6 mice (young: 6.1{plus minus}0. Read More

    Pregnancy late in rodent life has detrimental effects on the heart.
    Am J Physiol Heart Circ Physiol 2018 May 11. Epub 2018 May 11.
    Department of Molecular, Cellular, and Developmental Biology, BioFrontiers Institute and University of Colorado at Boulder, United States.
    During pregnancy, the heart undergoes significant and numerous changes, including hypertrophy that are usually described as physiological and reversible. Two aspects of the cardiac response to pregnancy are relatively understudied: advanced maternal age and multiple pregnancies (multiparity). Repeated breeder mice (RB) that have undergone 5 to 7 consecutive pregnancies were sacrificed 21 days after the weaning of their last pups and were compared to age-matched primiparous, one-time pregnant mice (O1P). Read More

    Brachial artery endothelial function is stable across a menstrual and oral contraceptive pill cycle, but lower in premenopausal women than age-matched men.
    Am J Physiol Heart Circ Physiol 2018 May 4. Epub 2018 May 4.
    Department of Kinesiology, McMaster University, Canada.
    Sex hormone concentrations differ between men, premenopausal women with natural menstrual cycles (NAT), and premenopausal women using oral contraceptive pills (OCP), as well as across menstrual or OCP phases. This study sought to investigate how differences in sex hormones, particularly estradiol, between men and women and across cycle phases, may influence brachial artery endothelial function. Fifty-three healthy adults (22{plus minus}3 yrs; 20 men, 15 NAT, 18 second, third or fourth generation OCP) underwent assessments of sex hormones and endothelial (flow-mediated dilation test, FMD) and smooth muscle (nitroglycerin test, NTG) function. Read More

    Activated NO pathway in uterine arteries during pregnancy in IUGR rat model.
    Am J Physiol Heart Circ Physiol 2018 May 4. Epub 2018 May 4.
    pharmacology and physiology, Universite de Montreal, Canada.
    Insufficient development of the utero-placental circulation may contribute to the development of intrauterine growth restriction (IUGR). We developed a rat model of IUGR by administering a low-sodium diet. This diet reduces maternal blood volume expansion and uteroplacental perfusion. Read More

    Arteriolar Vasodilation Involves Actin Depolymerization.
    Am J Physiol Heart Circ Physiol 2018 May 4. Epub 2018 May 4.
    Medical Pharmacology and Physiology, University of Missouri, United States.
    It is generally assumed that relaxation of arteriolar vascular smooth muscle occurs through hyperpolarization of the cell membrane, reduction in intracellular calcium concentration, and activation of myosin light chain phosphatase/inactivation of myosin light chain kinase. We hypothesized that vasodilation is related to depolymerization of F-actin. Cremaster muscles were dissected from rats under sodium pentobarbital anesthesia (50mg/kg). Read More

    Acute stimulation of the soluble guanylate cyclase does not impact on left ventricular capacitance in normal and hypertrophied porcine hearts in vivo.
    Am J Physiol Heart Circ Physiol 2018 May 4. Epub 2018 May 4.
    Medical Department, Div. of Cardiology, Charité Berlin Campus Virchow, Germany.
    Experimental data indicate that stimulation of the nitric oxide (NO) - soluble guanylate cyclase (sGC) - cyclic guanosine monophosphate (cGMP) - protein kinase G (PKG) pathway can increase left ventricular (LV) capacitance via phosphorylation of the myofilamental protein titin. We aimed to test whether acute pharmacological sGC stimulation with BAY 41-8543 would increase LV capacitance via titin phosphorylation in healthy and deoxycorticosteroneacetate (DOCA)-induced hypertensive pigs. Nine healthy, landrace pigs and seven pigs with DOCA-induced hypertension and LV concentric hypertrophy were acutely instrumented to measure LV end-diastolic pressure-volume-relationships (EDPVR) at baseline and during intravenous infusion of BAY 41-8543 (1 and 3 μg/kg/min for 30 min, respectively). Read More

    Hemodynamic effects of incremental lung hyperinflation.
    Am J Physiol Heart Circ Physiol 2018 May 4. Epub 2018 May 4.
    School of Health and Exercise Sciences, University of British Columbia, Canada.
    Dynamic hyperinflation (DH) is common in COPD and is associated with dyspnea and exercise intolerance. DH also has adverse cardiac effects, though the magnitude of DH and the mechanisms responsible for the hemodynamic impairment remain unclear. We hypothesized that incrementally increasing DH would systematically reduce left-ventricular (LV) end diastolic volume (LVEDV) and stroke volume (LVSV) due to direct ventricular interaction (DVI). Read More

    Hypoxic Conditioning in blood vessels and smooth muscle tissues: effects on function, mechanisms, and unknowns.
    Am J Physiol Heart Circ Physiol 2018 Apr 27. Epub 2018 Apr 27.
    Molecular and Cellular Physiology, University of Liverpool, United Kingdom.
    Hypoxic preconditioning, the protective effect of brief, intermittent hypoxic or ischemic episodes on subsequent more severe hypoxic episodes, has been known for thirty years from studies on cardiac muscle. The concept of hypoxic preconditioning has expanded; excitingly, organs beyond the heart, including brain, liver and kidney, also benefit. Preconditioning of vascular and visceral smooth muscles has received less attention, despite their obvious importance to health. Read More

    Mechanisms underlying the increased cardiac norepinephrine spillover in heart failure.
    Am J Physiol Heart Circ Physiol 2018 Apr 27. Epub 2018 Apr 27.
    Preclinical Critical Care Unit, Florey Institute of Neuroscience, Australia.
    Patients with heart failure (HF) have increased levels of cardiac norepinephrine (NE) spillover, which is an independent predictor of mortality. We hypothesized that this increase in NE spillover in HF depends not only on increases in sympathetic nerve activity (SNA), but also on changes in the mechanisms controlling NE release and re-uptake. Such changes would lead to differences between the increases in directly recorded SNA and NE spillover to the heart in HF. Read More

    The effect of sex, menstrual cycle phase, and monophasic oral contraceptive pill use on local and central arterial stiffness in young adults.
    Am J Physiol Heart Circ Physiol 2018 Apr 20. Epub 2018 Apr 20.
    Department of Kinesiology, McMaster University, Canada.
    Arterial stiffness is associated with increased cardiovascular disease risk. Previous sex-based investigations of local and central stiffness report inconsistent findings and have not controlled for menstrual cycle phase in women. There is also evidence that sex hormones influence the vasculature, but their impact on arterial stiffness across a natural menstrual (NAT) or oral contraceptive pill (OCP) cycle has been understudied. Read More

    Improving the quality of preclinical research echocardiography: Observations, training and guidelines for measurement.
    Am J Physiol Heart Circ Physiol 2018 Apr 20. Epub 2018 Apr 20.
    Cardiac Hypertrophy Laboratory, Baker Heart and Diabetes Institute, Australia.
    Informal training in preclinical research may be a contributor to the poor reproducibility of preclinical cardiology research and low rates of translation into clinical research and practice. Mouse echocardiography is a widely used technique to assess cardiac structure and function in drug intervention studies using disease models. The inter-observer variability (IOV) of clinical echocardiographic measurements has been shown to improve with formalized training, but preclinical echocardiography lacks similarly critical standardization of training. Read More

    A role for collagen IV in cardiovascular disease?
    Am J Physiol Heart Circ Physiol 2018 Apr 20. Epub 2018 Apr 20.
    Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Denmark.
    Over the past decade, studies have repeatedly found single nucleotide polymorphisms located in the COL4A1 and COL4A2 genes to be associated with cardiovascular disease (CVD), and the 13q34 locus harboring these genes is one of approximately 160 genome-wide significant risk loci for coronary artery disease. COL4A1 and COL4A2 encode the ⍺1- and ⍺2-chains of collagen IV, a major component of basement membranes in various tissues including arteries. In spite of the growing body of evidence indicating a role for collagen IV in CVD, remarkably few studies aim at directly investigating such a role. Read More

    Ondansetron Blocks Wildtype and p.F503L Variant Small Conductance Calcium Activated Potassium Channels.
    Am J Physiol Heart Circ Physiol 2018 Apr 20. Epub 2018 Apr 20.
    Indiana University School of Medicine, United States.
    The apamin-sensitive, small conductance, calcium-activated potassium (SK) current ( I) is encoded by KCNN genes. I importantly contributes to cardiac repolarization in conditions associated with reduced repolarization reserve. To test the hypothesis that I inhibition contributes to drug-induced long QT (diLQT) syndrome, we (1) screened for KCNN variants among patients with diLQT, (2) determined the properties of heterologously expressed wildtype and variant KCNN channels, and (3) determined if the 5-HT receptor antagonist ondansetron blocks I. Read More

    Ataxia-Telangiectasia Mutated Kinase Deficiency Impairs Autophagic Response Early During Myocardial Infarction.
    Am J Physiol Heart Circ Physiol 2018 Apr 13. Epub 2018 Apr 13.
    Biomedical Sciences, East Tennessee State University, United States.
    Ataxia-telangiectasia mutated kinase (ATM) is activated in response to DNA damage. We have previously shown that ATM plays a critical role in myocyte apoptosis and cardiac remodeling following myocardial infarction (MI). Here, we tested the hypothesis that ATM deficiency results in autophagic impairment in the heart early during MI. Read More

    Strategies for Optimal Cardiovascular Aging.
    Am J Physiol Heart Circ Physiol 2018 Apr 13. Epub 2018 Apr 13.
    Department of Integrative Physiology, University of Colorado Boulder, United States.
    This review summarizes the opening keynote presentation overview of the American Physiological Society conference on Cardiovascular Aging: New Frontiers and Old Friends held in Westminster, CO, in August 2017. Age is the primary risk factor for cardiovascular diseases (CVD). Without effective intervention, increased numbers of older adults in the future will translate to greater prevalence of CVD and related disorders. Read More

    Acute Effects of Device-Guided Slow Breathing on Sympathetic Nerve Activity and Baroreflex Sensitivity in Posttraumatic Stress Disorder.
    Am J Physiol Heart Circ Physiol 2018 Apr 13. Epub 2018 Apr 13.
    Nephrology, Emory University, United States.
    Posttraumatic stress disorder (PTSD) patients have elevated sympathetic nervous system (SNS) reactivity and impaired sympathetic and cardiovagal baroreflex sensitivity (BRS). Device-guided slow breathing (DGB) has been shown to lower blood pressure (BP) and sympathetic activity in other patient populations. We hypothesized that DGB acutely lowers BP, heart rate (HR), and improves BRS in PTSD. Read More

    Cardioprotection by Intermittent Hypoxia Conditioning: Evidence, Mechanisms and Therapeutic Potential.
    Am J Physiol Heart Circ Physiol 2018 Apr 13. Epub 2018 Apr 13.
    Integrative Physiology & Anatomy, University of North Texas Health Science Center.
    The calibrated application of limited duration, cyclic, moderately intense hypoxia-reoxygenation increases cardiac resistance to ischemia-reperfusion stress. These intermittent hypoxic conditioning (IHC) programs consistently produce striking reductions in myocardial infarction and ventricular tachyarrhythmias following coronary artery occlusion and reperfusion, and in many cases, improved contractile function and coronary blood flow. These IHC protocols are fundamentally different from those used to simulate sleep apnea, a recognized cardiovascular risk factor. Read More

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