What is the impact of central insulin on muscle sympathetic nerve activity (MSNA) and vascular conductance in the absence of peripheral insulin delivery? Listen as Associate Editor Dr. Jason Carter (Baylor University) interviews authors Neil McMillan and Dr. Jackie Limberg (both at University of Missouri), along with expert Dr. Manda Keller-Ross (University of Minnesota), about the new Short Report by McMillan et al. To gain a better understanding of the central sympathoexcitatory effects of insulin in humans, the authors recruited two groups of young, healthy individuals. One group served as a time control and the other group received intranasal insulin administration. McMillan et al. measured MSNA from the fibular nerve, combined with continuous monitoring of blood pressure and leg blood flow, before and after insulin administration. Limberg, McMillan and co-authors found that only the individuals who received insulin exhibited an increase in efferent sympathetic nervous system activity, which was coupled with peripheral vasoconstriction and increases in arterial blood pressure. How does this research influence our mechanistic understanding of the sympathetic and hemodynamic response to insulin? Listen now to find out.

Neil J. McMillan, Dain W. Jacob, Brian Shariffi, Jennifer L. Harper, Glen E. Foster, Camila Manrique-Acevedo, Jaume Padilla, and Jacqueline K. Limberg Effect of acute intranasal insulin administration on muscle sympathetic nerve activity in healthy young adults Am J Physiol Heart Circ Physiol, published July 3, 2024. DOI: 10.1152/ajpheart.00253.2024

Sometimes experimental results are serendipitous. Listen as Associate Editor Dr. Crystal Ripplinger (University of California, Davis) talks with authors Dr. Nikki Posnack and Devon Guerrelli (both at Children’s National Hospital and The George Washington University School of Engineering and Applied Science), along with expert Dr. Silvia Marchiano (University of Washington), about the new research by Guerrelli et al. published in our Call for Papers on Excitation-Contraction Coupling, Electrophysiology, and Arrhythmias. The Posnack Lab typically investigates environmental chemicals and their impact on cardiac function using microelectrode arrays to record electrical signals from human iPS cells. When performing cardiotoxicity experiments, the authors realized that their baseline measurements varied significantly between their different studies, making it difficult to combine datasets. In doing the legwork to identify potential sources of variability and improve their own internal lab protocols, the authors focused on the reproducibility of their experimental measurements using human iPSCs. Listen as we discuss important recommendations for investigators using these cells to improve their experimental reproducibility.

Devon Guerrelli, Jenna Pressman, Shatha Salameh, and Nikki Posnack hiPSC-CM Electrophysiology: Impact of Temporal Changes and Study Parameters on Experimental Reproducibility Am J Physiol Heart Circ Physiol, published June 9, 2024. DOI: 10.1152/ajpheart.00631.2023

Hormone modulation therapy is a growing area of research in cardiovascular science related to a number of factors, such as menopause and andropause, cancers in hormone-producing organs, as well as gender-affirming hormone therapy. So how do scientists and clinicians measure, monitor, and balance applications of hormone therapy? In our latest podcast, Associate Dr. Keith Brunt interviews authors Dr. Chantal Rytz (University of Calgary) and Dr. Sofia Ahmed (University of Alberta), along with expert Dr. Nina Stachenfeld (John B. Pierce Laboratory/Yale School of Medicine) about the recent article by Rytz et al. The authors review the use of estrogen in adult transgender, non-binary and gender diverse individuals who are medically managed with hormone modulation therapy for gender affirmation. Their findings indicate that the rate at which serum estrogen concentrations change may be important in order to optimize cardiovascular health and manage risk factors for obesity, hyperlipidemia, and elevated blood pressure. How should scientists account for and explore the hormone state of individuals within a cardiovascular context to improve the foundation of evidence for hormone modulation therapies for clinicians? Listen and learn more.

Chantal L. Rytz, Keila Turino Miranda, Paul E. Ronksley, Nathalie Saad, Satish R. Raj, Ranjani Somayaji, Sandra M. Dumanski, Heather Ganshorn, Dina N. Greene, David Collister, Amelia M. Newbert, Lindsay Peace, Sofia B. Ahmed Association between Serum Estradiol and Cardiovascular Health among Transgender Adults Using Gender-Affirming Estrogen Therapy Am J Physiol Heart Circ Physiol, published July 15, 2024. DOI: 10.1152/ajpheart.00151.2024