AJP-Heart and Circulatory Physiology Podcast

Mitochondrial Adaptations and Myocardial Energetics

The protective effect of ischemic preconditioning lasts for only a few hours, then reappears about a day later in what is termed the Second Window of Protection (SWOP). In this podcast Editor in Chief William Stanley interviews senior author Edward McFalls (VA Medical Center, University of Minnesota) and leading expert Nazareno Paolocci (Johns Hopkins University) about the work by Cabrera et al, which brings together an elegant animal model, cutting-edge proteomics technology, and clinical cardiologist and cardiovascular physiologist to uncover the role of the mitochondria and energetics in mediating SWOP.

Jesus A Cabrera, Elizabeth A Ziemba, Robert Colbert, Lorraine Anderson, Willem Sluiter, Dirk J. Duncker, Tammy A Butterick, Joseph Sikora, Herbert B Ward, Rosemary F Kelly, and Edward O McFalls. Altered Expression of Mitochondrial Electron Transport Proteins and Improved Myocardial Energetic State During Late Ischemic Preconditioning Am J Physiol Heart Circ Physiol, published ahead of print March 2, 2012, doi: 10.1152/ajpheart.00372.2011.

Photoplethysmography with Valsalva Maneuver Reflects Filling Pressure

What do Valsalva, the 17th century Italian physician, and smartphones have in common? Listen to our latest intriguing podcast which explores how the Valsalva Maneuver, when paired with finger photoplethysmography using a simple pulse oximetry probe, may provide cardiologists with an alternative to cardiac catheterization for heart failure patients. Associate Editor Ajay Shah interviews lead author Harry Silber (Johns Hopkins University) and expert Charles Chung (University of Arizona) about the work by Silber and colleagues, which knits together classical cardiovascular physiology, clinical cardiology, and inventive uses of existing technologies to provide insights into the left ventricular filling pressure of heart failure patients.

Harry A. Silber, Jeffrey C. Trost, Peter V. Johnston, W. Lowell Maughan, Nae-Yuh Wang, Edward K. Kasper, Thomas R. Aversano, and David E. Bush. Finger Photoplethysmography During the Valsalva Maneuver Reflects Left Ventricular Filling Pressure Am J Physiol Heart Circ Physiol, published ahead of print March 2, 2012, doi: 10.1152/ajpheart.00609.2011.

Hemin toxicity and autophagy

We know that hemin toxicity effects vascular endothelial cells, which may contribute to cardiovascular diseases. But what is the underlying molecular mechanism? In our newest podcast, Associate Editor Christine des Rosiers interviews senior author Victor Darley-Usmar (University of Alabama at Birmingham) and leading expert Neil Hogg (Medical College of Wisconsin) about the connections between lipid peroxidation in cells and its damaging effects on mitochondrial function, and the role autophagy may play in protecting those mitochondria from damage.

Ashlee N. Higdon, Gloria A. Benavides, Balu K. Chacko, Xiaosen Ouyang, Michelle S. Johnson, Aimee Landar, Jianhua Zhang, Victor M. Darley-Usmar. Hemin causes mitochondrial dysfunction in endothelial cells through promoting lipid peroxidation: the protective role of autophagy Am J Physiol Heart Circ Physiol, published online April 1, 2012, doi: 10.1152/ajpheart.00584.2011.

Nerve induced EC Ca2+ signals oppose vasoconstriction

Our latest podcast takes us into the realm of calcium pulsars. Associate Editor Nancy Kanagy talks with senior author Mark Nelson (University of Vermont) and leading expert Michael Hill (University of Missouri) about how the work of Nausch et al challenges the traditional view that the sympathetic nervous system regulates vascular tone independent of the endothelium. This work by Nelson and colleagues shows that the endothelium is dynamically engaged during neurovascular coupling through transcellular negative feedback which limits vasoconstriction. Listen as we explore how the vascular smooth muscle communicates with the endothelium, and the potential significance of this EDH mechanism to oppose sympathetically-mediated constriction.

Lydia W. M. Nausch, Adrian D. Bonev, Thomas J. Heppner, Yvonne Tallini, Michael I. Kotlikoff, Mark T. Nelson. Sympathetic nerve stimulation induces local endothelial Ca2+ signals to oppose vasoconstriction of mouse mesenteric arteries Am J Physiol Heart Circ Physiol, published ahead of print December 2, 2011, doi:10.1152/ajpheart.00773.2011.

In pursuit of scientific excellence - sex matters

Sex and gender matter in physiology, but are frequently ignored in scientific publications. In our latest podcast, Editor in Chief William Stanley has a lively conversation with leading experts Virginia Miller (Mayo Clinic) and Jane Reckelhoff (University of Mississippi) about the importance of sex and gender differences in physiology research and publications. Clear sex differences are apparent at the molecular, cellular and whole organ levels, prompting a new editorial policy for the American Physiological Society publications which requires reporting of the sex and/or gender of animals and humans, as well as all derived materials. Learn about how to approach this important issue in your work, and the surprising effects of sex on physiology from the molecular level on up.

Virginia M. Miller. In pursuit of scientific excellence - sex matters Am J Physiol Heart Circ Physiol, published ahead of print February 10, 2012, doi: 10.1152/ajpheart.00073.2012.

Fructose diet-induced cardiomyocyte Ca2+ cycling abnormality

In our latest podcast we explore the cardiac-specific effects of a high fructose diet. An inventive new study by Mellor et al investigates excitation contraction coupling changes in myocytes isolated from an experimental mouse model. These studies reveal, upon high fructose feeding, marked alterations in myocyte Ca2+ handling, but with maintained contractile function. Associate Editor Meredith Bond and leading expert Susan Howlett (Dalhousie University) interview senior author Lea Delbridge (University of Melbourne) about her exciting new work on diabetic cardiomyopathy.

Kimberley M Mellor, Igor R Wendt, Rebecca H Ritchie, and Lea M.D. Delbridge. Fructose diet treatment in mice induces fundamental disturbance of cardiomyocyte Ca2+ handling and myofilament responsiveness Am J Physiol Heart Circ Physiol, published ahead of print December 23, 2011, doi:10.1152/ajpheart.00797.2011.

Molecular mechanisms linking salt to hypertension

It is well known that there is no single cause of hypertension, but many of the factors that contribute to hypertension are known. Our latest podcast spotlights an elegant new Review article by Blaustein and colleagues which focuses on the interplay of salt and the secretion and action of endogenous ouabain. Associate Editor Irving Zucker interviews senior author, and fellow Associate Editor, Mordecai Blaustein (University of Maryland), along with leading expert John Osborn (University of Minnesota) about how endogenous ouabain might contribute to salt-sensitive hypertension and plays a central role in the alterations in the central nervous system, kidney and vasculature which contribute to chronic hypertension.

Mordecai P. Blaustein, Frans HH Leenen, Ling Chen, Vera A. Golovina, John M Hamlyn, Thomas L Pallone, James W. Van Huysse, Jin Zhang, Withrow Gil Wier. How NaCl raises blood pressure: A new paradigm for the pathogenesis of salt-dependent hypertension Am J Physiol Heart Circ Physiol, published ahead of print November 4, 2011, doi:10.1152/ajpheart.00899.2011.

BH4 and Vascular Function in Women

What's the problem with arterial function following menopause? Listen as Editor in Chief William Stanley, senior author Kerrie Moreau (University of Colorado Denver), and leading women’s health expert Virginia Miller (Mayo Clinic) engage in a lively conversation about the latest clinical study by Moreau et al on the role of estrogen and uncoupled nitric oxide synthase in arterial stiffening in post-menopausal women. Can early intervention with estrogen combat accelerated vascular aging after menopause?

Kerrie L Moreau, Amie Meditz, Kevin Deane, Wendy M. Kohrt. Tetrahydrobiopterin Improves Endothelial Function and Decreases Arterial Stiffness in Estrogen-Deficient Postmenopausal Women Am J Physiol Heart Circ Physiol, published ahead of print January 13, 2012, doi:10.1152/ajpheart.01065.2011.

Obesity and orthopedic trauma

The obesity epidemic in the United States shows no signs of abating, which is why our latest podcast is particularly insightful. Associate Editor Nancy Kanagy talks with author Lusha Xiang (University of Mississippi) and leading expert Jeff Frisbee (West Virginia University) about the study by Xiang and colleagues, which suggests the mechanism behind the poor prognosis for obese trauma victims and provides insight into a new therapeutic intervention to improve recovery of obese victims of traumatic injury.

Lusha Xiang, Silu Lu, William Fuller, Arun Aneja, George V Russell, Louis B Jones, and Robert L. Hester. Impaired blood pressure recovery to hemorrhage in obese Zucker rats with orthopedic trauma. Am J Physiol Heart Circ Physiol, published ahead of print October 14, 2011, doi: 10.1152/ajpheart.00439.2011.

Muscle oxygen transport and utilization in heart failure

A well-known problem for heart failure patients is the inability, or markedly decreased ability, to exercise. When even low levels of daily activity are impaired, the quality of life for heart failure patients suffers considerably. The mechanisms for exercise intolerance are very complicated and extend far beyond impaired cardiac performance. Listen in as Associate Editor Irving Zucker, senior author David Poole (Kansas State University) and leading expert Peter Wagner (University of California, San Diego) discuss the new Review article by Poole and colleagues, which tackles the mechanisms of muscle dysfunction in heart failure at the oxygen transport and microcirculatory levels.

David C. Poole, Daniel M. Hirai, Steven W. Copp, and Timothy I. Musch. Muscle Oxygen Transport and Utilization in Heart Failure: Implications for Exercise (In)tolerance Am J Physiol Heart Circ Physiol, published ahead of print November 18, 2011, doi:10.1152/ajpheart.00943.2011.