August 21, 2019
How do the immune system, nervous system, and renal system interact in the pathogenesis of hypertension? In this podcast Editor in Chief Irving H. Zucker (University of Nebraska Medical Center) interviews lead author Sailesh Harwani (University of Iowa) and content expert Liang Xiao (Vanderbilt University) about the new study by Raikwar et al, which used a spontaneously hypertensive rat model in a pre-hypertensive state to determine the causality of the multi-system components. The study design involved two interventions--complete bi-lateral renal denervation, and ablation of CD161a+ immune cells. The authors found that administering nicotine in the renal denervation group prevented cholinergic hypertension. Blood pressure elevation and renal inflammation were prevented in both the renal denervation and CD161a+ ablation intervention groups by administering nicotine. Does the location of CD161 immune cells at the vertex between the kidneys and immune systems play a pivotal role in how these cells are influenced by the adrenergic and cholinergic nervous systems? Listen and find out.
Nandita Raikwar, Cameron Braverman, Peter M. Snyder, Robert A. Fenton, David K. Meyerholz, Francois M. Abboud, and Sailesh C. Harwani Renal denervation and CD161a immune ablation prevent cholinergic hypertension and renal sodium retention Am J Physiol Heart Circ Physiol, published August 20, 2019. DOI: doi.org/10.1152/ajpheart.00234.2019
August 14, 2019
High plasma aldosterone is an independent risk factor for cardiac mortality, but what is known about the underlying mechanisms linking high levels of aldosterone to cardiac ischemic events? Listen as Consulting Editor Donal O’Leary (Wayne State University) interviews lead author Shawn Bender (University of Missouri & Truman VA) and expert Judy Muller-Delp (Florida State University) about the work led by motivated undergraduate Maloree Khan, which tested the hypothesis that increased plasma aldosterone impairs adenosine-mediated coronary vasodilation. Bender and co-authors found that high plasma aldosterone levels impaired adenosine A2A receptor-mediated dilation, but not adenosine A2B receptor-mediated vasodilation. Using a dose of aldosterone that does not significantly elevate blood pressure, Khan et al observed aldosterone-mediated changes in coronary dilation to adenosine via downregulation of calcium-activated potassium channels. Listen as these experts discuss the role of aldosterone and the mineralocorticoid receptor in ion channel expression in the vasculature, as well as future next steps related to sex differences and cell-specific knockout models.
Maloree Khan, Alex I. Meuth, Scott M. Brown, Bysani Chandrasekar, Douglas K. Bowles, and Shawn B. Bender Aldosterone impairs coronary adenosine-mediated vasodilation via reduced functional expression of Ca2+-activated K+ channels Am J Physiol Heart Circ Physiol, published June 14, 2019. DOI: doi.org/10.1152/ajpheart.00081.2019
August 7, 2019
Does 24 hours of total sleep deprivation affect older women and older men differently? Associate Editor Nisha Charkoudian (U.S. Army Research Institute for Environmental Medicine) interviews lead author Jason Carter (Michigan Technological University) and expert Nina Stachenfeld (Yale University School of Medicine) about the innovative study by Carter and co-authors, who found a sympatho-excitatory response to the sleep deprivation protocol in older women, but not in older men. The work by Carter et al suggests that the autonomic nervous system may have a larger role in older women who are sleep deprived, which is particularly important given that older women are at higher risk of developing hypertension than their age-matched male counterparts. Carter and colleagues conclude that "the association between sleep deprivation and hypertension is real." Will this new research kickstart a push for sleep as medicine for cardiometabolic diseases? Listen and find out.
Jason R. Carter, Ida T. Fonkoue, Ian M. Greenlund, Christopher E. Schwartz, Babak Mokhlesi, Carl A. Smoot Sympathetic Neural Responsiveness to Sleep Deprivation in Older Adults: Sex Differences Am J Physiol Heart Circ Physiol, published July 29, 2019. DOI: doi.org/10.1152/ajpheart.00232.2019