June 15, 2020
We know that smoking increases the risk of sudden cardiac death, which is linked to changes in ventricular repolarization. Is there a difference in sudden cardiac death risk between smoking tobacco cigarettes vs. e-cigarettes? Associate Editor Nisha Charkoudian (U.S. Army Research Institute for Environmental Medicine) interviews lead author Holly Middlekauff (University of California Los Angeles) and content expert Marmar Vaseghi (University of California Los Angeles) about the new study by Ip et al. In this study, the authors compared electrocardiogram indices of ventricular repolarization in tobacco smokers before and after smoking a tobacco cigarette, as well as e-cigarette vapers before and after smoking an e-cigarette—once with and once without nicotine. Acute nicotine intake was the same among both types of smokers. However, three ECG indices of repolarization were significantly prolonged in tobacco smokers after smoking, whereas one of three indices was prolonged in e-cigarette smokers after vaping. What do these findings indicate about the sudden cardiac death risk of e-cigarettes compared to tobacco cigarettes? Does the e-cigarette rate of nicotine delivery have an impact on physiological effects? Listen now to learn how to present an evidence-based argument the next time a friend (or your child) tells you e-cigarettes are “safer” than smoking.
Michelle Ip, Evangelos Diamantakos, Kacey Haptonstall, Yasmine Choroomi, Roya S. Moheimani, Kevin Huan Nguyen, Elizabeth Tran, Jeffrey Gornbein, Holly R. Middlekauff Tobacco and electronic cigarettes adversely impact ECG indexes of ventricular repolarization: implication for sudden death risk Am J Physiol Heart Circ Physiol, published April 21, 2020. DOI: doi.org/10.1152/ajpheart.00738.2019
May 29, 2020
Women develop post-traumatic stress disorder (PTSD) at twice the rate of men, and women with PTSD are at higher risk for developing hypertension. Yet little research has been done to date investigating the mechanisms mediating the link between PTSD and cardiovascular disease in women. The study by Yoo et al. seeks to change that. Associate Editor Donal O’Leary (Wayne State University School of Medicine) interviews lead author Qi Fu (The Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas) and expert Adam Case (University of Nebraska Medical Center) about the groundbreaking and clinically-relevant study by Fu and co-authors. The authors showed for the first time that women with PTSD had a greater pressor response during the cold pressor test compared with healthy women. What insights did Fu and collaborators uncover when they compared results from traditional methods to quantify integrated nerve signals, and a novel wavelet-based technique used to identify differences in MSNA responses to cold pressor test between women with PTSD and healthy women? Do Fu and Case anticipate that the current COVID-19 pandemic, while undeniably tragic, may eventually open new avenues of discovery for how women with PTSD differ from healthy counterparts and men? Listen and learn.
Jeung-Ki Yoo, Mark B. Badrov, Mu Huang, Ryan A. Bain, Raymond P. Dorn, Elizabeth H. Anderson, Jessica L. Wiblin, Alina Suris, J. Kevin Shoemaker, Qi Fu Abnormal sympathetic neural recruitment patterns and hemodynamic responses to cold pressor test in women with posttraumatic stress disorder Am J Physiol Heart Circ Physiol, published April 27, 2020. DOI: 10.1152/ajpheart.00684.2019
May 25, 2020
In this episode of Behind the Bench with AJP-Heart and Circ hosted by Lisandra de Castro Bras (East Carolina University) and Jonathan Kirk (Loyola University Chicago), we talk with Charlotte Usselman, Assistant Professor in Kinesiology and Physical Education at McGill University. Charlotte’s recently published article is a culmination of research that began in the summer of 2016 during her post-doc at the John B. Pierce Laboratory at Yale School of Medicine. One year into the project, Charlotte was offered a position at McGill, which she postponed for 6 months to finish collecting data at Yale. In 2018, she focused heavily on getting her new lab up and running, and did not focus on her preeclampsia research. Charlotte’s story is living proof that things don’t always go as planned, much like having a preeclamptic pregnancy. Sometimes our lives outside of work are hard, even painful, and this certainly informs how we move forward personally and professionally. But a collision of timing can sometimes result in unexpected success. How? Listen.
Charlotte W. Usselman, Tessa E. Adler, Yasmine Coovadia, Cheryl Leone, Michael J. Paidas, Nina S. Stachenfeld A recent history of preeclampsia is associated with elevated central pulse wave velocity and muscle sympathetic outflow Am J Physiol Heart Circ Physiol, published March 3, 2020. DOI: doi.org/10.1152/ ajpheart.00578.2019
May 22, 2020
What are the best practices for animal models of exercise training? Associate Editor Mario Delmar (New York University) kickstarts a conversation with expert physiologists David Poole (Kansas State University), Timothy Musch (Kansas State University), Steven Copp (Kansas State University), Michael Sturek (Indiana University), Donal O’Leary (Wayne State University), and our own Editor in Chief Irv Zucker (University of Nebraska Medical Center) about the new Guidelines in Cardiovascular Research article by Poole et al. This landmark Guidelines article is designed to provide researchers with comprehensive information as they navigate selecting the most appropriate animal species and exercise paradigm to use in their exercise studies. As Tim Musch points out, “Exercise tests are many times the best strategy for determining the presence and severity of disease.” As the authors explain, animal models offer researchers the ability to control for disease severity and duration, confounding drug treatments, invasive procedures, as well as acute and chronic exercise interventions. We cover rat, mouse, dog, pig, and rabbit exercise training, and discuss everything from which incentive (dark chocolate or cocoa puffs?) rats prefer to thoroughbred racehorses! Listen now.
David C. Poole, Steven W. Copp, Trenton D. Colburn, Jesse C. Craig, David L. Allen, Michael Sturek, Donal S. O’Leary, Irving H. Zucker, Timothy I. Musch Guidelines for animal exercise and training protocols for cardiovascular studies Am J Physiol Heart Circ Physiol, published April 21, 2020. DOI: doi.org/10.1152/ajpheart.00697.2019
May 22, 2020
High fructose consumption is associated with metabolic syndrome, but the mechanisms are not well understood. Listen as Associate Editor Fabio Recchia (Temple University and Scuola Superiore Sant'Anna) interviews lead author An Huang (New York Medical College) and content expert Zsolt Bagi (Medical College of Georgia) about the new study by Froogh et al, which used an animal model to test the hypothesis that a high fructose diet elicits a chymase-dependent increase in angiotensin II production and oxidative stress. In this technical tour de force of a podcast, we unpack the complexities of EET as a protective factor against oxidative stress. Listen as our experts discuss metabolic syndrome in the context of COVID-19, as well as the potential clinical translation of chymase and soluble epoxide hydrolase as therapeutic targets for the treatment of metabolic syndrome.
Ghezal Froogh, Sharath Kandhi, Roopa Duvvi, Yicong Le, Zan Weng, Norah Alruwaili, Jonathan O. Ashe, Dong Sun, An Huang The contribution of chymase-dependent formation of ANG II to cardiac dysfunction in metabolic syndrome of young rats: roles of fructose and EETs Am J Physiol Heart Circ Physiol, published April 2, 2020. DOI: doi.org/10.1152/ ajpheart.00633.2019
May 7, 2020
We know that blood pressure increases with age, and that a large part of the global population takes at least one blood pressure lowering medication. Could acute leg heating be used as a non-pharmacological therapy to lower blood pressure in aged adults? In our latest podcast, Associate Editor Nisha Charkoudian (U.S. Army Research Institute of Environmental Medicine) interviews lead author Steven Romero (University of North Texas Health Science Center) and expert Charlotte Usselman (McGill University) about the new study by Engelland et al. Romero and co-authors examined the neurovascular mechanisms through which acute isolated leg heating reduced arterial blood pressure in an older cohort of healthy adults compared to healthy younger adults. While sympathetic nerve activity did not differ from preheat to recovery in aged adults, this group experienced a marked reduction in blood pressure. Does this response vary by sex or is neurovascular transduction altered on an acute time scale? Listen to find out the answers to these questions as we cover this hot topic.
Rachel E. Engelland, Holden W. Hemingway, Olivia G. Tomasco, Albert H. Olivencia-Yurvati, Steven A. Romero Neural control of blood pressure is altered following isolated leg heating in aged humans Am J Physiol Heart Circ Physiol, published April 2, 2020. DOI: doi.org/10.1152/ajpheart.00019.2020
April 30, 2020
While the global community struggles to cope with the COVID-19 pandemic, our latest episode investigates what role the angiotensin-converting enzyme 2 (ACE2) plays in the internalization of the novel SARS coronavirus SARS-CoV-2. Editor in Chief Irving H. Zucker (University of Nebraska Medical Center) interviews lead author Mark C. Chappell (Wake Forest University) and expert Paul McCray (University of Iowa) about the new Perspective by South et al on “COVID-19, ACE2 and the Cardiovascular Consequences.” We discuss whether the deleterious effects of SARS-CoV-2 are mediated through increasing Ang-II or augmenting the activity of ACE2. In this wide-ranging conversation our experts also discuss the kidney, the small intestine, and the heart—organs which express ACE2 and may be targeted by infection through viremia. We also touch on why the African American community has been disproportionately affected by COVID-19, sex differences, additional co-morbidities, and ACE-inhibitors. Listen now.
Andrew M. South, Debra I. Diz, and Mark C. Chappell COVID-19, ACE2, and the cardiovascular consequences Am J Physiol Heart Circ Physiol, published April 13, 2020. DOI: doi.org/10.1152/ajpheart.00217.2020
April 27, 2020
In this episode of Behind the Bench, Lisandra de Castro Bras (East Carolina University) and Jonathan Kirk (Loyola University Chicago) talk with Michael Sayegh, an MD/PhD student in the joint Wallace H. Coulter Department of Biomedical Engineering at Emory University and Georgia Tech. A rotation project with Hee Cheol Cho at Georgia Tech culminated in a first-author publication in AJP-Heart and Circ in June 2019. When we talked with Michael to get the scoop behind his science, we were struck by his humility and gratitude. Our conversation uncovers the catalyst for Michael to pursue becoming a physician scientist, the sometimes-daunting amount of training this involves, and of course, how all of this relates to Harry Potter. Michael’s personal story as an immigrant from Aleppo, Syria, who used a dial-up connection to apply to Harvard and Yale, shows where perseverance, determination and good luck can lead. If anything, we could all use an inspirational story right about now.
Michael N. Sayegh, Natasha Fernandez, and Hee Cheol Cho Strength-duration relationship as a tool to prioritize cardiac tissue properties that govern electrical excitability Am J Physiol Heart Circ Physiol, published June 14, 2019. DOI: doi.org/10.1152/ajpheart.00161.2019
February 17, 2020
How can researchers ensure that Doppler ultrasound measurements of human resistance vessel function are both accurate and repeatable? Listen as Editor in Chief Dr. Irving H. Zucker (University of Nebraska Medical Center) interviews the lead authors of this Guidelines in Cardiovascular Research article— Jacqueline K. Limberg (University of Missouri), Jaume Padilla (University of Missouri), Darren P. Casey (University of Iowa), Joel Trinity (University of Utah). The authors discuss the need for clear inclusion and exclusion criteria for human subjects, as well as the necessity of avoiding several key environmental stressors for a period of time prior to assessments. As a result of collaborating with experts around the globe, the authors developed a comprehensive figure and tables to outline considerations surrounding medication use and the potential impact of medication on vascular function, as well as other concerns for study participants such as caffeine intake, alcohol use, posture, and sleep. What is the best ambient room temperature to avoid confounding results related to skin blood flow when evaluating total limb blood flow to skeletal muscle? For the answer to this key question and more, listen now.
Jacqueline K. Limberg, Darren P. Casey, Joel D. Trinity, Wayne T. Nicholson, D. Walter Wray, Michael E. Tschakovsky, Daniel J. Green, Ylva Hellsten, Paul J. Fadel, Michael J. Joyner, Jaume Padilla Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology Am J Physiol Heart Circ Physiol, published January 31, 2020. DOI: doi.org/10.1152/ajpheart.00649.2019
February 11, 2020
In this episode, Jonathan Kirk (Loyola University Chicago) and Lisandra de Castro Bras (East Carolina University) talk with Ninette Shenouda, an ambitious and savvy researcher at the University of Delaware. While finishing her PhD at McMaster University, Ninette co-authored two papers investigating the influence of sex hormones on flow-mediated dilation. While conducting her experiments, Ninette mastered the deceptively complex technique of measuring FMD and navigated some unpredictable situations with study participants. It was an APS Connect job posting that led Ninette to her current post-doc position, in which she has expanded her skill set by studying pulsatile load and connections between heart and brain function in kidney disease. Ninette speaks with refreshing honesty and wisdom about a pivotal moment early in her PhD when she wondered if she could trust her data, and the choice she faced to either stay discouraged or “find a way to get better.” Clearly Ninette chose the latter. This podcast will resonate with every trainee. We cover the importance of becoming affiliated with a professional society in your area of research, thinking two steps ahead of your current position, and perhaps the most valuable take-away: developing expertise which round out your skill portfolio to make you uniquely marketable. Oh, and #ScienceRomance is a thing. Listen now.
Ninette Shenouda, Stacey E. Priest, Vanessa I. Rizzuto, Maureen J. MacDonald Brachial artery endothelial function is stable across a menstrual and oral contraceptive pill cycle but lower in premenopausal women than in age-matched men Am J Physiol Heart Circ Physiol, published August 8, 2019. DOI: doi.org/10.1152/ajpheart.00102.2018
Stacey E. Priest, Ninette Shenouda, and Maureen J. MacDonald Effect of sex, menstrual cycle phase, and monophasic oral contraceptive pill use on local and central arterial stiffness in young adults Am J Physiol Heart Circ Physiol, published August 8, 2019. DOI: doi.org/10.1152/ ajpheart.00039.2018