March 31, 2017
What are the best technological and methodological guidelines for measuring sympathetic nerve activity in humans and animals? In this *special edition* podcast, Editor in Chief Irving H. Zucker (University of Nebraska Medical Center) interviews lead authors, and leading experts, Nisha Charkoudian (U.S. Army Research Institute of Environmental Medicine), Jason Carter (Michigan Technological University), Geoffrey Head (Baker IDI Heart and Diabetes Institute), and John Osborn (University of Minnesota) about this comprehensive tour de force article of Guidelines in Cardiovascular Physiology by Hart et al. Bringing together nine global experts to collaborate and build a consensus on best practices for measuring SNA took over a year to accomplish, and the Editors of AJP-Heart and Circ are both exceptionally grateful to the authors and proud to publish this guidelines article –the first of its kind for the journal! Listen as Jason Carter and Nisha Charkoudian discuss human microneurography, the main validation techniques and the potential pitfalls to recording multi-unit and single unit activity. Continue listening as John Osborn and Geoff Head discuss optimal sympathetic recording techniques in experimental animals, the “do’s and don’ts” of recording SNA in conscious animals, surgical techniques needed, and avoiding artifactual data. This conversation is unlike any other podcast in cardiovascular journals. Don’t miss the opportunity to hear these experts discuss their work, their collaboration, and the net result—comprehensive guidelines for measuring sympathetic nerve activity. Listen now.
Emma C. J. Hart, Geoffrey A Head, Jason R. Carter, Gunnar Wallin, Clive N May, Shereen M Hamza, John E. Hall, Nisha Charkoudian, John W. Osborn Recording sympathetic nerve activity in conscious humans and other mammals: guidelines and the road to standardization Am J Physiol Heart Circ Physiol, published March 31, 2017. DOI: 10.1152/ajpheart.00703.2016
March 28, 2017
What exactly is cardiac denervation, and can it have an anti-arrhythmic effect in the setting of chronic myocardial infarction? Listen as Associate Editor Mario Delmar (New York University) interviews lead author Marmar Vaseghi (UCLA Cardiac Arrhythmia Center) and Consulting Editor and content expert Crystal Ripplinger (University of California, Davis) about this translational study by Vaseghi and colleagues, which used a porcine model to determine if bilateral cardiac sympathetic denervation reduced ventricular tachy-arrhythmia inducibility in both normal and infarcted hearts. What are the possible short-term and long-term changes in the regulation of the inotropic response resulting from the denervation? What are the cellular mechanisms responsible for changes in action potential durations? Listen to find out.
Tadanobu Irie, Kentaro Yamakawa, David Hamon, Keijiro Nakamura, Kalyanam Shivkumar, Marmar Vaseghi Cardiac sympathetic innervation via middle cervical and stellate ganglia and antiarrhythmic mechanism of bilateral stellectomy Am J Physiol Heart Circ Physiol, published March 1, 2017. DOI: 10.1152/ajpheart.00644.2016
March 15, 2017
Is macrophage MMP-9 a prime upstream regulator of cardiac aging? Yes, according to new research by Toba et al, explored in our latest podcast. Editor in Chief Irving H. Zucker (University of Nebraska Medical Center) interviews lead author and Deputy Editor Merry Lindsey (University of Mississippi Medical Center) and content expert Richard Gumina (Vanderbilt University) about the work by Lindsey and colleagues, which expands our knowledge of macrophage MMP-9 overexpression and its amplification of the myocyte hypertrophic response to aging. Did Lindsey and co-authors find in their experimental model that diastolic cardiac physiology was impaired before systolic cardiac physiology? MMP-9 appears to be a driver of inflammation, rather than a consequence of inflammation. Does MMP-9 in the aged heart also play a pro-fibrogenic role? Listen and learn more.
Hiroe Toba, Presley L. Cannon, Andriy Yabluchanskiy, Rugmani Padmanabhan Iyer, Jeanine D’Armiento, Merry L. Lindsey Transgenic overexpression of macrophage matrix metalloproteinase-9 exacerbates age-related cardiac hypertrophy, vessel rarefaction, inflammation, and fibrosis Am J Physiol Heart Circ Physiol, published March 1, 2017. DOI:10.1152/ajpheart.00633.2016
March 6, 2017
Is the vascular response in humans to the diving reflex genetically determined? In our first-ever podcast recorded in both Russian and English, Associate Editor Debra I. Diz (Wake Forest University School of Medicine) interviews lead author Tatiana I. Baranova (St.-Petersburg State University, Russia), her translator Vladimir Boykov, and content expert Charles E. Wood (University of Florida). Listen as we explore the work by Baranova and co-authors, which determined that polymorphisms in the bradykinin and renin-angiotensin systems are the driving force behind hemodynamic responses to the diving reflex. What is known about the functional implications of the mutations that affect the coding regions of the genes ADBR2, ACE, AGTR1, BDKRB2, and REN? Does this work on the genomics of hemodymic changes during transient hypoxia have potential therapeutic applications in personalized medicine? Listen to find out.
Tatiana I. Baranova, Dmitrii N. Berlov, Oleg S. Glotov, Ekaterina A. Korf, Alexey D. Minigalin, Alla V. Mitrofanova, Ildus I Ahmetov, Andrey S. Glotov Genetic determination of the vascular reactions in humans in response to the diving reflex Am J Physiol Heart Circ Physiol, published online December 6, 2016. DOI: 10.1152/ajpheart.00080.2016