AJP-Heart and Circulatory Physiology Podcast

Post-translational Modifications of Cardiac Proteasomes

What are the big questions surrounding our understanding of post-translational modifications (PTMs) of proteasomes? Associate Editor Meredith Bond interviews lead author Nobel Zong (UCLA) and expert Xuejun Wang (University of South Dakota) about the latest Review article by Scruggs et al from the lab of Peipei Ping and colleagues. Why are the reversible and permanent PTMs of proteasomes critical to our understanding of cardiac physiology? How will we correlate changes in PTMs of proteasomes with pathological and physiological changes in heart function? How will we deal with the increasingly large data sets generated? Listen now…

Sarah B. Scruggs, Nobel C. Zong, Ding Wang, Enrico Stefani, and Peipei Ping Post-translational Modification of Cardiac Proteasomes: Functional Delineation Enabled by Proteomics Am J Physiol Heart Circ Physiol, published online April 20, 2012, doi: 10.1152/ajpheart.00189.2012.

Thromboxane A2-induced Vasoconstriction in Pregnant Rats

The vascular physiology of pregnancy still provide us with surprising observations. In our latest podcast, Associate Editor Nancy Kanagy interviews author Stella Goulopoulou (Georgia Health Sciences University) and leading expert George Osol (University of Vermont College of Medicine) about the new research published by Goulopoulou and colleagues. This work found that the contractile response to thromboxane in uterine arteries is mediated by a surprisingly unique signal transduction pathway. Will further exploration lead to new therapeutic targets for vascular abnormalities in pregnancy during conditions such as preeclampsia? Listen in and find out.

Styliani Goulopoulou, Johanna L. Hannan, Takayuki Matsumoto, and R. Clinton Webb Pregnancy reduces RhoA/Rho kinase and protein kinase C signaling pathways downstream of thromboxane receptor activation in rat uterine artery Am J Physiol Heart Circ Physiol, published online April 27, 2012, doi:10.1152/ajpheart.00900.2011.

Cerebrovascular Response After Long Duration Spaceflight

We tackle our most unique topic yet-- long duration spaceflight! In the micro-gravity environment of spaceflight, fluid shifts from the feet to the head. Over time this fluid shift increases pressure in the brain, a particular concern for long duration spaceflight astronauts. Listen as Consulting Editor John Longhurst interviews senior author Richard Hughson (University of Waterloo) and leading expert Ronney Panerai (University of Leicester) about alterations in cerebrovascular function pre- and post- long duration spaceflight, including anecdotes about the challenges of experiments involving astronauts in both the U.S.A. and Russia.

Kathryn A. Zuj, Philippe Arbeille, J. Kevin Shoemaker, Andrew P. Blaber, Danielle K. Greaves, Da Xu, and Richard L. Hughson Impaired cerebrovascular autoregulation and reduced CO2 reactivity after long duration spaceflight Am J Physiol Heart Circ Physiol, published online April 6, 2012, doi: 10.1152/ajpheart.00029.2012.

Age-related Changes in Central Blood Pressures

What happens when you combine NSAID type pain medication and aging-induced arterial stiffening? Can cyclooxygenase inhibitors cause hemodynamic problems in older adults? Editor-in-chief Bill Stanley interviews lead author Jill Barnes (Mayo Clinic) and expert Judy Delp (University of Florida) about the new human study by Barnes and colleagues which looked at the central blood pressure response to the COX inhibitor indomethacin in both old and young healthy adults.

Jill Nicole Barnes, Darren P. Casey, Caesy N. Hines, Wayne T. Nicholson, and Michael J. Joyner Cyclooxygenase Inhibition Augments Central Blood Pressure and Aortic Wave Reflection in Aging Humans Am J Physiol Heart Circ Physiol, published online April 13, 2012, doi: 10.1152/ajpheart.00032.2012.

Cytochrome P450 2C9 and Coronary Resistance Vessel Tone

Understanding the underlying mechanisms of increased coronary blood flow during exercise is the pursuit of many cardiovascular researchers worldwide. Here, Associate Editor Masafumi Kitakaze interviews lead author Dirk Duncker (Erasmus University Medical Center) and expert Masaru Sugimachi (National Cardiovascular Center, Osaka) about the new study by Zhou et al on the vasodilator and vasoconstrictor metabolites produced by cytochrome P-450 (CYP) 2C9 in pigs both at rest and during exercise. Listen in to learn how Duncker and colleagues used innovative in vivo and in vitro experimental conditions, achieving surprisingly different results related to the effects of sulfaphenazole in the presence of combined NOS/COX blockade.

Zhichao Zhou, Veemal Hemradj, Vincent J. de Beer, Fen Gao, Maaike Hoekstra, Daphne Merkus, and Dirk J. Duncker Cytochrome P-450 2C9 exerts a vasoconstrictor influence on coronary resistance vessels in swine at rest and during exercise Am J Physiol Heart Circ Physiol, published online February 3, 2012, doi:10.1152/ajpheart.00648.2011.

Neuregulin1/ErbB4 Signaling and Cardiomyocyte Proliferation

How is cardiac neuregulin signaling involved after herceptin treatment of breast cancer patients? Our latest podcast explores the new Review article by Wadugu et al, which focuses on neuregulin signaling in the heart and dissects early observations that up to 30% of patients treated with herceptin for breast cancer displayed heart failure as a side-effect, likely by inhibiting neuregulin signaling. Cardiomyocyte proliferation is just one of many events triggered by neuregulin activation in heart cells, thereby opening a safe, paracrine possibility to stimulate myocyte proliferation in experimental and clinical heart failure studies. Listen as Associate Editor Leon de Windt talks with senior author Bernhard Kuhn (Children's Hospital Boston/Harvard Medical School) and leading expert Douglas Sawyer (Vanderbilt University) about stem cell treatments, clinical trials, and much more.

Brian Wadugu and Bernhard Kuhn. The role of neuregulin/ErbB2/ErbB4 signaling in the heart with special focus on effects on cardiomyocyte proliferation Am J Physiol Heart Circ Physiol, published ahead of print March 16, 2012, doi: 10.1152/ajpheart.00063.2012.

O-GlcNAc Signaling During Hypertrophy

Does protein glycosylation drive cardiac hypertrophy? In our latest podcast, Editor in Chief William Stanley talks with senior author Steven P. Jones (University of Louisville) and leading expert John Chatham (University of Alabama at Birmingham) to discuss the work by Facundo et al that explores the role of O-GlcNAc in pathological cardiac hypertrophy through NFAT modification. Listen as they discuss the complexities and importance of O-GlcNAc signaling, and explore the methodological challenges in assessing protein O-GlcNAcylation. Is there a role in heart failure or diabetic cardiomyopathy? Listen in and find out.

Heberty T. Facundo, Robert E. Brainard, Lewis J Watson, Gladys A. Ngoh, Tariq Hamid, Sumanth D. Prabhu, and Steven P. Jones O-GlcNAc Signaling is Essential for NFAT-Mediated Transcriptional Reprogramming During Cardiomyocyte Hypertrophy Am J Physiol Heart Circ Physiol, published ahead of print March 9, 2012, doi: 10.1152/ajpheart.00775.2011.

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.