AJP-Heart and Circulatory Physiology Podcast

Particulate Matter Induced Vascular Insulin Resistance

How are diet-independent insulin resistance and defects in endothelial progenitor cell mobilization altered by particulate matter exposure? Find out by listening to this engaging podcast as Guest Editor Loren Wold (The Ohio State University) interviews lead author Petra Haberzettl (University of Louisville) and content expert Timothy Nurkiewicz (West Virginia University) about the recent study by Haberzettl et al published as part of our Call for Papers on Cardiovascular Responses to Environmental Stress. Haberzettl and co-authors used a mouse model to investigate exposure to fine particulate matter, altered sensitivity of blood vessels, and an inflammatory pathway. What “chicken and egg” problem does NOS uncoupling and oxidative stress pose, related to decreased insulin sensitivity via Akt? Does this work challenge the current literature to look beyond cytokines and interleukin-mediated processes to endothelial progenitor cells in the bone marrow? Listen and learn.

Petra Haberzettl, James P. McCracken, Aruni Bhatnagar, Daniel J. Conklin Insulin sensitizers prevent fine particulate matter-induced vascular insulin resistance and changes in endothelial progenitor cell homeostasis Am J Physiol Heart Circ Physiol, published June 1, 2016. DOI: 10.1152/ajpheart.00369.2015

Effects of Age and Estrogen on Cerebrovascular Function

Does aging enhance the deleterious effects of exogenous estrogen in the female cerebrovasculature? In this engaging new podcast, Guest Editor Akos Koller (New York Medical College, Valhalla, and University of Physical Education, Budapest) interviews lead author John Stallone (Texas A & M University) and content expert Ines Drenjancevic (University of Osijek, Croatia) about the intriguing new work by Deer et al, which studied the interplay of vascular prostanoids, estrogen, and aging in small cerebral arteries. Why did the authors choose vasopressin to study the reactivity of the cerebral vasculature? How does the uncoupling of nitric oxide synthase to produce oxygen free radicals relate to aging? How does aging convert estrogen from a beneficial to a deleterious hormone? Listen and find out.

Rachel R. Deer, John N. Stallone Effects of estrogen on cerebrovascular function: age-dependent shifts from beneficial to detrimental in small cerebral arteries of the rat Am J Physiol Heart Circ Physiol, published May 15, 2016. DOI: 10.1152/ajpheart.00645.2015.

Diastolic Dysfunction in the Hypertensive mRen2 Rat

Do basic scientists now have a good animal model of heart failure with preserved ejection fraction (HFpEF) that mimics the human pathology? It’s very likely, according to the recent work by Kovacs et al. In this podcast, Editor in Chief Irving H. Zucker interviews lead author Arpad Kovacs (University of Debrecen, Hungary) and content expert Nazha Hamdani (VU University Medical Center, Amsterdam, and Ruhr University, Germany) about the fascinating new work by Kovacs and co-authors which seeks to understand the interplay between the renin-angiotensin-aldosterone system (RAAS) and hypertension in the unique mRen2 rat model of HFpEF. What role do the titin filament network and collagen fibers of the extracellular matrix play in LV diastolic dysfunction? Do the mechanisms underlying diastolic dysfunction hold the key to understanding if the hypertension associated with mRen2 rats is unique to this model or an inevitable consequence of hypertension? Listen now.

Árpád Kovács, Gabor Aron Fulop, Andrea Kovacs, Tamas Csipo, Beata Bodi, Daniel Priksz, Bela Juhasz, Lívia Beke, Zoltán Hendrik, Gábor Méhes, Henk Granzier, Istvan Edes, Miklós Fagyas, Zoltán Papp, Judit Barta, Attila Tóth Renin overexpression leads to increased titin-based stiffness contributing to diastolic dysfunction in hypertensive mRen2 rats Am J Physiol Heart Circ Physiol, published April 8, 2016. DOI: 10.1152/ajpheart.00842.2015

Dilated Cardiomyopathy Delta Sarcoglycan Mutations Cause Cardiomyocyte Membrane Instability

What is the link between mutations in delta sarcoglycans and dilated cardiomyopathy? In our latest podcast, Guest Editor Noah Weisleder (Ohio State University) interviews lead author Daniel Michele (University of Michigan) and content expert Aaron Beedle (University of Georgia) about this very question, digging deeper into the elegant study by Campbell et al which reveals that two different delta sarcoglycan mutations indeed have a dominant negative effect on myocyte membrane mechanical stability. Using a variety of experimental approaches—cellular, biochemical and functional assays—Dr. Michele and co-authors help to uncover the relationship between these genetic mutations and the presentation of the dilated cardiomyopathy phenotype. Learn more about how a personal connection to muscular dystrophy acted as a springboard for this study, part of our Call for Papers on Plasma Membrane Integrity in Cardiovascular Physiology and Pathophysiology. How do delta sarcoglycans guard against sarcolemma instability, and how does membrane repair differ from membrane integrity in dilated cardiomyopathy? Listen and find out.

Matthew D. Campbell, Marc Witcher, Anoop Gopal, Daniel E. Michele Dilated cardiomyopathy mutations in δ-sarcoglycan exert a dominant-negative effect on cardiac myocyte mechanical stability Am J Physiol Heart Circ Physiol, published May 1, 2016. DOI: 10.1152/ajpheart.00521.2015

Aging Impairs Endothelial Ca2+ Signaling

We know that as we age, blood vessels become less effective at getting blood where you need it, when you need it. Intracellular calcium signaling is a key step in regulation of vascular function. Could defects in calcium signaling between the endothelium and smooth muscle cells of microvessels contribute to aging-related vascular dysfunction? Listen as Guest Editor Akos Koller (New York Medical College, Valhalla, and University of Physical Education, Budapest) interviews first author Erika Boerman (University of Missouri - Columbia) and topic expert Jonathan Ledoux (Montreal Heart Institute) about an innovative Rapid Report by Boerman and colleagues. Using an intravital microvascular preparation, Boerman et al combined several innovative techniques from other laboratories, including GCamp 2 mice developed as a calcium biosensor for measuring calcium pulsars, to explore calcium signaling in holes within the internal elastic lamina between the endothelium and smooth muscle. If the number of these holes reduces with aging, is there a corresponding decreased capacity for myoendothelial calcium signaling, which then can contribute to age-related microvascular dysfunction? Listen and learn.

Erika M. Boerman, Jesse E. Everhart, Steven S. Segal Advanced age decreases local calcium signaling in endothelium of mouse mesenteric arteries in vivo Am J Physiol Heart Circ Physiol, published May 1, 2016. DOI: 10.1152/ajpheart.00038.2016.

CpG DNA and Maternal Vascular Function

Preeclampsia affects nearly 10 million pregnancies worldwide every year, and is still a major cause of maternal death globally, particularly in developing countries. So why isn’t more known about the initiation of gestational hypertension? In their recent work published in AJP-Heart and Circulatory Physiology, Goulopoulou et al seek to change that. Listen as Associate Editor Nancy Kanagy interviews Stella Goulopoulou (University of North Texas Health Science Center) and leading expert Lawrence Reynolds (North Dakota State University) about the work by Goulopoulou and co-authors, which used an innovative mitochondrial DNA analog, ODN 2395, to induce activation of toll-like receptor 9 and stimulate maternal pregnancy hypertension in rats. Does placenta cell death released into the maternal circulation trigger the innate immune system to induce a systemic inflammatory response resulting in pregnancy-induced hypertension? Could CpG oligonucleotides from bacterial infections play a role in preeclampsia? Listen and find out.

Styliani Goulopoulou, Camilla F. Wenceslau, Cameron G. McCarthy, Takayuki Matsumoto, R. Clinton Webb Exposure to stimulatory CpG oligonucleotides during gestation induces maternal hypertension and excess vasoconstriction in pregnant rats Am J Physiol Heart Circ Physiol, published April 15, 2016. DOI: 10.1152/ajpheart.00834.2015.

Cardiac Adaptations During a Mountain Ultra-Marathon

Can a mountain ultra-marathon—arguably the most grueling and strenuous form of extreme exercise—be good for your heart? That’s just what we discuss in this latest podcast. Listen as Editor-in-Chief Dr. Irv Zucker interviews lead author Stéphane Nottin (Montpellier I University & Nimes University Hospital Center) and leading expert Michael Joyner (Mayo Clinic) about the work Nottin and colleagues undertook measuring the effects of this type of extreme exercise on the cardiac function of runners before, during, and after the world's most challenging mountain ultra-marathon Tor des Géants in the Italian Alps. While traipsing echocardiographic equipment around the Alps is no small feat, the results of Nottin and co-authors were even more interesting. As opposed to races of shorter duration or less extreme conditions (a typical marathon course, for example), post-race cardiac function improved in the ultra-marathoners. What role does exercise intensity play in these measurements of improved cardiac function? Why does end-diastolic volume increase at the end of the race, and does an increase in plasma volume explain the increase in gastric function in racers? Listen to find out.

Claire Maufrais, Grégoire P. Millet, Iris Schuster, Thomas Rupp, Stéphane Nottin Progressive and biphasic cardiac responses during extreme mountain ultra-marathon Am J Physiol Heart Circ Physiol, published February 26, 2016. DOI: 10.1152/ajpheart.00037.2016.

Astronaut Arterial Stiffness and Insulin Resistance

Is exercise really the best medicine…in space? In this fascinating podcast, Consulting Editor David Gutterman (Medical College of Wisconsin) interviews lead author Richard Hughson (University of Waterloo) and content expert Walter Wray (University of Utah) about the latest work by Hughson and co-authors on how zero gravity alters vascular stiffness and insulin resistance, particularly in vessels in the head and neck. This latest work from Hughson and colleagues has important implications for long-term spaceflight, like missions to Mars and space station inhabitation. In addition, comparisons to bed rest studies make the case that acute changes in vascular stiffness may be treated with exercise, but how much is enough? With the recent completion of NASA astronaut Scott Kelly’s year in space, this podcast is not only timely, it is literally “out of this world.” Listen now.

Richard L. Hughson, Andrew D. Robertson, Philippe Arbeille, J. Kevin Shoemaker, James W. E. Rush, Katelyn S. Fraser, Danielle K. Greaves Increased postflight carotid artery stiffness and inflight insulin resistance resulting from 6-mo spaceflight in male and female astronauts Am J Physiol Heart Circ Physiol, published March 1, 2016. DOI: 10.1152/ajpheart.00802.2015.

Gender Differences in Acute Decompensated Heart Failure

Do we need to better understand gender differences in order to understand the pathophysiology of heart failure? Yes, according to a new study by Nakada et al. In the English version of this dual language podcast, listen as Associate Editor Masafumi Kitakaze interviews lead author Yoshihiko Saito (Nara Medical University) and guest expert Tomoko Ichiki (Mayo Clinic) about the work by Saito and colleagues, which analyzed the differences in prognostic power of plasma B-type natriuretic peptide (BNP) levels in men and women, as well as gender differences in age and ejection fraction distribution among heart failure patients. How do the results of Saito and colleagues, which clearly show that the pathophysiology of heart failure differs between men and women, impact potential clinical treatment strategies? Listen and learn more.

Yasuki Nakada, Rika Kawakami, Tomoya Nakano, Akihiro Takitsume, Hitoshi Nakagawa, Tomoya Ueda, Taku Nishida, Kenji Onoue, Tsunenari Soeda, Satoshi Okayama, Yukiji Takeda, Makoto Watanabe, Hiroyuki Kawata, Hiroyuki Okura, Yoshihiko Saito Gender Differences in Clinical Characteristics and Long-Term Outcome in Acute Decompensated Heart Failure Patients with Preserved and Reduced Ejection Fraction Am J Physiol Heart Circ Physiol, published online January 8, 2016, DOI: 10.1152/ajpheart.00602.2015.

JAPANESE LANGUAGE PODCAST: Gender Differences in Acute Decompensated Heart Failure

Do we need to better understand gender differences in order to understand the pathophysiology of heart failure? Yes, according to a new study by Nakada et al. In the Japanese version of this dual language podcast, listen as Associate Editor Masafumi Kitakaze interviews lead author Yoshihiko Saito (Nara Medical University) and guest expert Tomoko Ichiki (Mayo Clinic) about the work by Saito and colleagues, which analyzed the differences in prognostic power of plasma B-type natriuretic peptide (BNP) levels in men and women, as well as gender differences in age and ejection fraction distribution among heart failure patients. How do the results of Saito and colleagues, which clearly show that the pathophysiology of heart failure differs between men and women, impact potential clinical treatment strategies? Listen and learn more.

Yasuki Nakada, Rika Kawakami, Tomoya Nakano, Akihiro Takitsume, Hitoshi Nakagawa, Tomoya Ueda, Taku Nishida, Kenji Onoue, Tsunenari Soeda, Satoshi Okayama, Yukiji Takeda, Makoto Watanabe, Hiroyuki Kawata, Hiroyuki Okura, Yoshihiko Saito Gender Differences in Clinical Characteristics and Long-Term Outcome in Acute Decompensated Heart Failure Patients with Preserved and Reduced Ejection Fraction Am J Physiol Heart Circ Physiol, published online January 8, 2016, DOI: 10.1152/ajpheart.00602.2015.