Racial Differences in Serum Sodium and Blood Pressure Regulation

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PROJECT SUMMARY / ABSTRACT CANDIDATE: Austin T. Robinson, Ph.D is a Postdoctoral Associate at the University of Delaware (UD). Dr. Robinson aims to study racial differences in cardiovascular responses to high dietary sodium (Na+). He recently published data demonstrating that compared to white individuals, 1) black individuals have augmented increases in serum Na+ to a hypertonic saline infusion; and 2) exhibit higher blood pressure (BP) for a given serum Na+. In this proposal, he will translate these findings by comprehensively assessing neurovascular responses to acute (single meal) and chronic (10 days of a controlled feeding) high dietary Na+. The central hypothesis is that high dietary Na+ influences sympathetic nerve activity similarly in black and white individuals; however, diminished vasodilator capacity and augmented sympathetic transduction (vasoconstrictor responses to sympathetic nerve bursts) contribute to exaggerated BP dysregulation in black individuals. He will also determine the role of lifestyle factors (i.e., sleep, physical activity, and nutrition) on potential baseline racial differences in CV physiology. CAREER DEVELOPMENT PLAN: Dr. Robinson proposes to enhance his career development by: 1) Acquiring new skills in the assessment of sleep, assessment of (nitric oxide) NO. bioavailability, and assessment of reactive oxygen species (ROS). 2) Advanced training in epidemiology to analyze large data sets. Specifically, he will perform secondary data of samples collected for the Multi-Ethnic Study of Atherosclerosis (MESA) under the guidance of advisor Dr. Norrina Allen, an expert epidemiologist. 3) Refining his professional skills though formal course work, attendance and presentations at weekly journal clubs, and at national/international scientific meetings. ENVIRONMENT: Dr. Robinson will train in an outstanding research environment supported by a multi- disciplinary team of mentors. The primary mentor, Dr. Farquhar, is an NHLBI-funded full professor at UD with a record of successful mentorship. He is an expert in autonomic control of circulation, and executing controlled salt feeding studies. Co-mentor Dr. Edwards is also at UD and a leading expert in vascular physiology function and executing controlled dietary salt feeding studies. Co-mentor Dr. Brown is an expert in lifestyle as a preventive and treatment strategy for hypertension and vascular function in black individuals. Advisors Dr. Zimmerman and Dr. Poole are experts in ROS and NO. signaling, respectively. Advisor Dr. Buxton is a recognized expert in sleep and health consequences of sleep deficiency, especially cardiometabolic outcomes. Advisor Dr. Wright is a professor in Nursing at UD and has expertise in neuropsychology and racial disparities. RESEARCH: Black individuals are more prone to salt-sensitive elevations in BP and adverse cardiovascular conditions associated with chronic high dietary Na+ intake compared to other racial groups. Racial disparities in vascular function and, autonomic control of BP in black individuals under basal conditions also exist. There is a critical need to elucidate the physiology underlying these racial disparities and to determine if these racial disparities are attributable to lifestyle differences.