AJP-Heart and Circulatory Physiology Podcast

JAPANESE VERSION: Liposomal Erythropoietin Protects the Heart

NEW! In this JAPANESE language podcast, Associate Editor Masafumi Kitakaze interviews lead author Shinya Minatoguchi (Gifu University Graduate School of Medicine, Gifu, Japan) and expert Tetsuji Miura (Sapporo Medical University School of Medicine, Sapporo, Japan) about the innovative new work by Yamada et al which used liposomal erythropoietin therapy to reduce infarct size in a rabbit heart model. Can this relatively non-invasive drug delivery method become an effective way to reduce infarct size in acute MI human patients? Listen now.

Yoshihisa Yamada, Hiroyuki Kobayashi, Masamitsu Iwasa, Shohei Sumi, Hiroaki Ushikoshi, Takuma Aoyama,
Kazuhiko Nishigaki, Genzou Takemura, Takako Fujiwara, Hisayoshi Fujiwara, Makoto Kiso, and Shinya Minatoguchi Postinfarct active cardiac-targeted delivery of erythropoietin by liposomes with sialyl Lewis X repairs infarcted myocardium in rabbits Am J Physiol Heart Circ Physiol, published online February 15, 2013, doi: 10.1152/ajpheart.00707.2012.

DPP-IV Inhibitor Improves Survival in Murine Heart Failure

Can diabetes treatments also protect the heart? In our latest podcast we explore the work by Takahashi et al, which examined what a DPP-IV inhibitors will do at the level of the heart. Associate Editor Gary Lopaschuk interviews lead author Masanori Asakura (National Cerebral and Cardiovascular Center, Osaka, Japan) and expert Zam Kassiri (University of Alberta) about this exciting new work which pulls together aspects of metabolism, heart failure, anti-diabetic agents and cardioprotection. Listen and learn more.

Ayako Takahashi, Masanori Asakura, Shin Ito, Kyung-Duk Min, Kazuhiro Shindo, Yi Yan, Yulin Liao, Satoru Yamazaki, Shoji Sanada, Yoshihiro Asano, Hatsue Ishibashi-Ueda, Seiji Takashima, Tetsuo Minamino, Hiroshi Asanuma, Naoki Mochizuki, and Masafumi Kitakaze Dipeptidyl-Peptidase IV Inhibition Improves Pathophysiology of Heart Failure and Increases Survival Rate in Pressure-Overloaded Mice Am J Physiol Heart Circ Physiol, published online March 15, 2013, doi: 10.1152/ajpheart.00454.2012.

Coronary Vasoconstriction in Heart Failure Impairs Contractility

Can an abnormal metaboreflex activation causing coronary constriction help to explain the reduced ability of the heart to increase cardiac performance in heart failure patients during exercise? While the metaboreflex has been studied for decades, new research by Coutsos et al in a chronic dog model of heart failure gives fresh insights on how ventricular function is improved by relieving vasoconstriction and thus enhancing coronary blood flow. Associate Editor Fabio Recchia interviews lead author Donal O’Leary (Wayne State University) and expert Antonio Crisafulli (University of Cagliari, Italy) about this interesting work and its potential clinical impact on heart failure patients.

Matthew Coutsos, Javier A. Sala-Mercado, Masashi Ichinose, ZhenHua Li, Elizabeth J. Dawe, and Donal S. O'Leary Muscle Metaboreflex-Induced Coronary Vasoconstriction Limits Ventricular Contractility During Dynamic Exercise in Heart Failure Am J Physiol Heart Circ Physiol, published online January 25, 2013, doi: 10.1152/ajpheart.00879.2012.

Mitochondrial Calcium in mdx Myocytes

How is Ca2+ cycling in the heart altered in cardiomyopathy in Duchenne muscular dystrophy? Does a lack of the cytoskeletal protein dystrophin cause a perturbation in communication between L-type calcium channels and mitochondria? In our latest podcast on the work by Viola et al., Associate Editor Meredith Bond hosts a discussion with lead author Livia Hool (The University of Western Australia) and expert Angela Dulhunty (Australian National University). We examine the effect of disruption of the myocyte cytoskeleton in the mdx mouse model. We address the role of the myocyte cytoskeleton in regulating communication between plasma membrane and mitochondria, and we tackle potential clinical applications for muscular dystrophy patients. Listen now.

Helena M. Viola, Stefan M. K. Davies, Aleksandra Filipovska, and Livia C. Hool L-type Ca2+ channel contributes to alterations in mitochondrial calcium handling in the mdx ventricular myocyte Am J Physiol Heart Circ Physiol, published online January 18, 2013, doi: 10.1152/ajpheart.00700.2012.

Secondary SR Ca2+ Release and Arrhythmia Risk in Bradycardia

Our latest podcast explores the newly published article by Kim et al. In this work, lead author Guy Salama (University of Pittsburgh) and colleagues found that by prolonging action-potential duration, bradycardia may destabilize calcium and cause arrhythmia. Associate Editor Igor Efimov leads an engaging discussion with Salama and expert Steven Poelzing (Virginia Tech) about how intracellular calcium can affect cardiac electrophysiology, and through calcium-voltage coupling, can become the original source of arrhythmia. We also take a look at gender differences in remodeling and arrhythmogenesis, and the possible role estrogen may play in the susceptibility of the female heart to bradycardia-mediated arrhythmias.

Jong J. Kim, Jan Nemec, Rita Papp, Robert Strongin, Jonathan J Abramson, and Guy Salama Bradycardia alters Ca2+ dynamics which enhances dispersion of repolarization and arrhythmia risk Am J Physiol Heart Circ Physiol, published online January 11, 2013, doi: 10.1152/ajpheart.00787.2012.

G6PD Deficiency and Cardiovascular Disease

What can we learn from the most common enzyme deficiency in the world? Quite a lot, actually. G6PD deficiency has cascading effects on NADPH, reactive oxygen species production, and anti-oxidant reserves, all outlined in a comprehensive new Review article by Hecker et al. Associate Editor Ajay Shah interviews first author Peter Hecker (Washington University in St. Louis) as well as leading expert, and Associate Editor, Ronglih Liao (Brigham and Women's Hospital and Harvard Medical School) about compartmentalization, potential drug therapies, and where the study of G6PD deficiency will lead to next.

Peter A. Hecker, Jane A. Leopold, Sachin A. Gupte, Fabio A. Recchia, and William C. Stanley Impact of glucose-6-phosphate dehydrogenase deficiency on the pathophysiology of cardiovascular disease Am J Physiol Heart Circ Physiol, published online December 15, 2012, doi: 10.1152/ajpheart.00721.2012.

MSC-induced Cx43 Expression in Cardiomyocytes

We break it down for you: what really are the factors and mechanisms of cell replacement therapy? What are the mechanisms by which transplanted MSCs exert their paracrine effects? Associate Editor Ivor Benjamin interviews lead author Kathrin Banach (University of Illinois at Chicago) and expert Timothy Kamp (University of Wisconsin - Madison) about the recent work by Mureli et al, which has significant translational implications for cell therapy after ischemic injury. Listen and learn more..

Shwetha Mureli, Christopher P. Gans, Dan J. Bare, David L. Geenen, Nalin M. Kumar, and Kathrin Banach Mesenchymal Stem Cells Improve Cardiac Conduction by Up-Regulation of Connexin 43 Through Paracrine Signaling Am J Physiol Heart Circ Physiol, published online December 15, 2012, doi: 10.1152/ajpheart.00533.2012.

Sex Differences and Vascular Reactivity to Mental Stress

Do men and women handle mental stress differently? What role do sex differences play in the transduction of muscle sympathetic nerve activity (MSNA) into vascular tone during stress? Associate Editor Irving Zucker explores the recent work by Yang et al in our new podcast interview with lead author Jason Carter (Michigan Technological University) and expert Nisha Charkoudian (U.S. Army Research Institute of Environmental Medicine) in a stimulating conversation germane to the wave of research on sex differences in cardiovascular science. Listen now.

Huan Yang, Thomas Drummer, and Jason R. Carter Sex differences in sympathetic neural and limb vascular reactivity to mental stress in humans Am J Physiol Heart Circ Physiol, published online November 30, 2012, doi: 10.1152/ajpheart.00688.2012.

Endothelin-1 and Exercise

How can we tame the sleeping giant of excess skeletal muscle blood flow during exercise? In our latest podcast we expand our understanding of the role endothelin-1 plays in regulating skeletal muscle blood flow during whole body, as well as targeted, exercise in healthy patients. Consulting Editor David Gutterman leads this interesting conversation with author Walter Wray (University of Utah) and expert Kevin Dellsperger (University of Missouri-Columbia) about the recent work by Barrett-O’Keefe et al. What are the possibilities for targeting the endothelin-1 pathway in disease states? Listen now.

Zachary Barrett-O'Keefe, Stephen J. Ives, Joel Douglas Trinity, Richard Garrett Morgan, Matthew Jordan Rossman, Anthony J. Donato, Sean Runnels, David E. Morgan, Benjamin S. Gmelch, Amber D. Bledsoe, Russell S. Richardson, and D. Walter Wray Taming the "Sleeping Giant": The Role of Endothelin-1 in the Regulation of Skeletal Muscle Blood Flow and Arterial Blood Pressure during Exercise Am J Physiol Heart Circ Physiol, published online October 26, 2012, doi:10.1152/ajpheart.00603.2012.

MMPs: Milestones, Myths, and (Mis)Perceptions

So you thought that the role of matrix metalloproteinases (MMPs) in myocardial remodeling had been all worked out? Well, it's not so simple. The latest Review article by Iyer et al debunks myths and demystifies perceptions surrounding MMPs and their role in regulating the extracellular matrix and cardiac structure. In our new podcast, Editor in Chief William Stanley interviews lead author Merry Lindsey (University of Texas Health Science Center San Antonio) and expert Loren Wold (The Research Institute at Nationwide Children's Hospital) about the work by Lindsey and others in the MMP/TIMP field. Listen now to discover more.

Rugmani Padmanabhan Iyer, Nicolle L. Patterson, Gregg B. Fields, and Merry L. Lindsey The history of matrix metalloproteinases: milestones, myths, and misperceptions Am J Physiol Heart Circ Physiol, published online August 17, 2012, doi: 10.1152/ajpheart.00577.2012.