AJP-Heart and Circulatory Physiology Podcast

Right Ventricular Metabolic Adaptations to Exercise Training

What exactly is happening in the metabolism of the exercising individual? Listen as Associate Editor Gary Lopaschuk (University of Alberta, Canada) interviews lead author Kari Kalliokoski (University of Turku, Finland) and content expert Michael Nelson (University of Texas at Arlington) about the work by Heiskanen et al, which studied energy metabolism in the heart during cardiac hypertrophy that was not pathological, but rather a result of exercise. Kalliokoski and colleagues measured changes in myocardial metabolism for healthy, untrained individuals who participated in either high intensity interval training (HIIT) or moderate intensity continuous aerobic training. Using PET imaging, once with a euglycemic hyperinsulinemic clamp and once in a traditional fasting state, Kalliokoski and co-authors studied the right ventricular response to exercise and its training adaptation. Did the HIIT training group achieve better results with just 3 minutes of exercise, compared to the moderate intensity aerobic group which exercised 40 – 60 minutes? Listen now.

Marja A. Heiskanen, Tuija Leskinen, Ilkka H. A. Heinonen, Eliisa Löyttyniemi, Jari-Joonas Eskelinen, Kirsi Virtanen, Jarna C. Hannukainen, Kari K. Kalliokoski Right ventricular metabolic adaptations to high-intensity interval and moderate-intensity continuous training in healthy middle-aged men Am J Physiol Heart Circ Physiol, published September 1, 2016. DOI: 10.1152/ajpheart.00399.2016

Habitual Exercise and Systolic Blood Pressure During Resistance Exercise

Elevations in systolic blood pressure during both resistance and cardiovascular exercise, and during regular daily activities, are predictive in the development of cardiovascular disease. Can higher levels of general physical activity reduce the rise in systolic blood pressure that occurs with resistance exercise? Listen as Consulting Editor David Gutterman (Medical College of Wisconsin) interviews lead author Takeshi Otsuki (Ryutsu Keizai University, Japan) and content expert Shane Phillips (University of Illinois-Chicago) about the work by Otsuki and colleagues which combined both observational and interventional human studies involving moderate intensity exercise programs. Is blood pressure during exercise a more sensitive predictor of cardiovascular risk than resting blood pressure? Does brachial arterial stiffness affect blood pressure during exercise? Listen and find out.

Takeshi Otsuki, Takahiro Kotato, Asako Zempo-Miyaki Habitual exercise decreases systolic blood pressure during low-intensity resistance exercise in healthy middle-aged and older individuals Am J Physiol Heart Circ Physiol, published October 1, 2016. DOI: 10.1152/ajpheart.00379.2016

miR140 and Right Heart Hypertrophy

Is there one microRNA playing a primary role in the complex pathogenesis of right ventricular failure caused by pulmonary hypertension? Listen as Associate Editor Fabio Recchia (Temple University Lewis Katz School of Medicine, and Scuola Superiore Sant'Anna, Pisa, Italy) interviews lead author Sachin Gupte (New York Medical College) and content expert Paras Mishra (University of Nebraska Medical Center) about the work by Joshi et al, which used microarray analysis to focus on MiR140 as a potential therapeutic target in a Sugen5416/hypoxia/normoxia model of pulmonary arterial hypertension (PAH). Is MiR31 also a major player in the pathogenesis of this disease? What is the translational relevance of the work by Gupte and colleagues on afterload-induced right ventricular failure? Listen to find out.

Sachindra Raj Joshi, Vidhi Dhagia, Salina Gairhe, John G. Edwards, Ivan F. McMurtry, Sachin A Gupte MicroRNA-140 is elevated and mitofusin-1 is downregulated in the right ventricle of the Sugen5416/Hypoxia/Normoxia model of pulmonary arterial hypertension Am J Physiol Heart Circ Physiol, published July 15, 2016. DOI: 10.1152/ajpheart.00264.2016

AngII and Aging-Induced Endothelial Dysfunction

Aging, as we all know, is unavoidable and leads to an increased risk for vascular dysfunction and cardiovascular pathologies. So what are the mechanisms responsible for aging-induced vascular dysfunction? That’s just what Flavahan et al set out to investigate in their latest work in AJP-Heart and Circ. Listen as Editor in Chief Dr. Irving H. Zucker (University of Nebraska Medical Center) interviews lead author Nick Flavahan (Johns Hopkins University) and content expert Edward Lakatta (National Institute on Aging, National Institutes of Health) about Flavahan’s work, which builds on previous studies by Lakatta. Chronic in vivo inhibition of angiotensin activity protects endothelial function, but is it due to blockade of the systemic Renin-Agiotensin System (RAS) or the local vascular angiotensin system? What role do changes in anti-oxidant scavenging mechanisms play in endothelial dysfunction associated with aging? How do flow-mediated dilation and changes in angiotensin receptor expression fit into the big picture of aging? Listen and find out.

Sheila Flavahan, Fumin Chang, Nicholas A. Flavahan Local Renin-Angiotensin System Mediates Endothelial Dilator Dysfunction in Aging Arteries Am J Physiol Heart Circ Physiol, published July 15, 2016. DOI: 10.1152/ajpheart.00422.2016

Sympathetic Reactivity and Family History of Hypertension

How does family history of hypertension contribute to sympathetic neural control of blood pressure, and what role does mental stress play in blood pressure regulation? The latest work by Fonkue et al seeks to answer these very questions. Listen as Consulting Editor Nisha Charkoudian (U.S. Army Research Institute of Environmental Medicine) interviews lead author Jason Carter (Michigan Technological University) and content expert Megan Wenner (University of Delaware) about the study by Carter and colleagues, which used microneurography to measure muscle sympathetic nerve activity (MSNA) during an acute bout of mental stress (performing mental math) in both women and men with, and without, a family history of hypertension. Can evaluations of larger groups over several years help determine if the sympathetic nervous system plays an essential role in the development of hypertension in those with a family history of the disease? Listen and find out.

Ida T. Fonkoue, Min Wang, Jason R. Carter Sympathetic neural reactivity to mental stress in offspring of hypertensive parents: 20 years revisited Am J Physiol Heart Circ Physiol, published July 1, 2016. DOI: 10.1152/ajpheart.00378.2016

Vascular Health After Preeclampsia

What is the mechanism behind the increased risk for cardiovascular and renal diseases in women who have previously suffered from early-onset preeclampsia? Listen as Associate Editor Robert Hester (University of Mississippi Medical Center) interviews lead author Anne Marijn van der Graaf (University of Groningen Medical Center) and content expert Ira Bernstein (University of Vermont Medical Center) about the clinical study by van der Graaf and colleagues, which compared the arterial stiffness of healthy women with a history of preeclamptic pregnancy to healthy women with no preeclamptic pregnancy history after low sodium and high sodium diets. Were formerly preeclamptic women able to adjust their arterial stiffness after eating a low sodium diet? What is the role of vessel wall function and the glycocalyx as markers of vascular stiffness? Listen and find out.

Anne Marijn van der Graaf, Nina D. Paauw, Tsjitske J. Toering, Martin Feelisch, Marijke M. Faas, Thomas R. Sutton, Magdalena Minnion, Joop D. Lefrandt, Sicco A. Scherjon, Arie Franx, Gerjan Navis, A. Titia Lely Impaired sodium-dependent adaptation of arterial stiffness in formerly preeclamptic women: the RETAP-vascular study Am J Physiol Heart Circ Physiol, published June 1, 2016. DOI: 10.1152/ajpheart.00010.2016

Acetylation Control of Energy Metabolism in Newborn Hearts

How well do we understand the post-translational molecular mechanisms regulating changes in metabolism in the newborn heart? This podcast seeks the answer, as Associate Editor Ajay Shah (King’s College London, British Heart Foundation Centre of Excellence) interviews lead author Gary Lopaschuk (University of Alberta) and content expert Luc Bertrand (Université catholique de Louvain) about the work by Fukushima et al, which found rapid acetylation of a number of fatty acid oxidative enzymes, and increased fatty acid oxidation activity, in the newborn rabbit heart. Why is increased expression of mitochondrial acetyltransferase GCN5L1 important in the changes observed by Lopaschuk and colleagues? Could this be a “master regulator” of protein acetylation? Listen and find out.

Arata Fukushima, Osama Abo Alrob, Liyan Zhang, Cory S Wagg, Tariq Altamimi, Sonia Rawat, Ivan M. Rebeyka, Paul F. Kantor, Gary D. Lopaschuk Acetylation and Succinylation Contribute to Maturational Alterations in Energy Metabolism in the Newborn Heart Am J Physiol Heart Circ Physiol, published June 3, 2016. DOI: 10.1152/ajpheart.00900.2015

Chronic Vagal Nerve Stimulation in Stroke-Prone SHR

Can restoring parasympathetic nerve activity in patients with primary hypertension prevent cardiovascular end organ damage? In this podcast Associate Editor Debra Diz (Wake Forest University School of Medicine) interviews lead author Harald Stauss (University of Iowa) and content expert Douglas Martin (University of South Dakota) about the study by Chapleau et al. Referred to as a “a technological tour de force” that combined chronic vagal nerve stimulation, chronic telemetric blood pressure measurements, and in vivo imaging of the long posterior ciliary artery (LPCA) using the slit lamp approach to assess endothelial function, the authors found that endothelial function improved, without changes in blood pressure. Does this approach have the potential to interrupt the pathway between blood pressure and end organ damage, when lowering blood pressure could lead to adverse clinical ramifications in elderly fall risk patients, for example? Listen and learn.

Mark W. Chapleau, Diane L Rotella, John J Reho, Kamal Rahmouni, Harald M. Stauss Chronic Vagal Nerve Stimulation Prevents High-Salt Diet-Induced Endothelial Dysfunction and Aortic Stiffening in Stroke-Prone Spontaneously Hypertensive Rats Am J Physiol Heart Circ Physiol, published May 20, 2016. DOI: 10.1152/ajpheart.00043.2016

Hypothermia/Rewarming Disrupts E-C Coupling

What is the connection between Tromso, Norway, hypothermia, rewarming, heart failure…and AJP-Heart and Circ? Listen to this fascinating new podcast as Associate Editor Leon De Windt (Cardiovascular Research Institute Maastricht) interviews lead author Gary Sieck (Mayo Clinic) and content expert Jolanda van der Velden (VU University Medical Center Amsterdam) about the intriguing and entirely unique work by Schaible at al, which explores how to protect the heart during rewarming after hypothermia. Whatever the cause of hypothermia—falling into a fjord, skiing accident—inadequate rewarming at a trauma center and/or restarting the heart in the field by first responders can both lead to heart failure. Listen as we discuss how hypothermia can inhibit the SERCA pump, as well as affect the sodium-calcium exchanger, slowing the clearance of calcium. Is it possible for a hypothermic person in asystole, if CPR is administered to restore circulation, to later be rewarmed and survive without any deficits or long-term side effects? Listen and find out.

Niccole Schaible, Young Soo Han, Thuy Hoang, Grace Arteaga, Torkjel Tveita, Gary Sieck Hypothermia/rewarming disrupts excitation-contraction coupling in cardiomyocytes Am J Physiol Heart Circ Physiol, published June 1, 2016. DOI: 10.1152/ajpheart.00840.2015

Purinergic Dysregulation in Pulmonary Hypertension

What role do circulating nucleotides play in the pathobiology of pulmonary arterial hypertension (PAH)? In this new podcast Associate Editor Robert Hester (University of Mississippi Medical Center) interviews lead author Scott Visovatti (University of Michigan) and content expert Nikki Jernigan (University of New Mexico Health Sciences Center) about the clinically important work by Visovatti and colleagues investigating whether CD39—an extracellular nucleotidase responsible for the dephosphorylation of ATP—could be a key trigger for idiopathic PAH. By first investigating human blood and tissue samples of pulmonary arterial hypertension patients, followed by data from a unique CD39 knockout hypoxic mouse model, Visovatti and co-authors gained valuable insight into the PAH phenotype. What two “rescue approaches” did the authors use to lower right ventricular and pulmonary pressures in the CD39 mouse model? Listen and find out.

Scott H Visovatti, Matthew C Hyman, Sascha N Goonewardena, Anuli C. Anyanwu, Yogendra Kanthi, Patrick Robichaud, Jintao Wang, Danica Petrovic-Djergovic, Rahul Rattan, Charles F. Burant, David J Pinsky Purinergic dysregulation in pulmonary hypertension Am J Physiol Heart Circ Physiol, published May 20, 2016. DOI: 10.1152/ajpheart.00572.2015