Research Interests
Dr. Lapu-Bula has had a long-standing interest in the clinical applications of echo-Doppler techniques to the evaluation and risk stratification of patients with left ventricular dysfunction and chronic heart failure. As lead investigator in the NASA human cardiovascular studies at Morehouse School of Medicine, he has been working on the implementation of ultrasound protocols for use in human SMLSRC/NSBRI research on the effects of acute (12 h) and chronic (over 2 weeks) bed rest deconditioning on the cardiovascular system. The purpose is to evaluate the relative contribution of cardiac compliance and peripheral vasculature to orthostatic intolerance following exposure to long-term bed rest and to provide potential countermeasures. This work has been critical from the view point of NASA cardiovascular research, as it provides rapid non-invasive means to monitor cardiac volumetric and structural changes in humans during simulated microgravity, where other conventional imaging modalities could not efficiently be used. This research has also provided much needed data on the variability of cardiac mass and volumes to blood pressure changes under conditions of bed rest, with salt manipulations as countermeasures. Using this human model of blood pressure sensitivity to salt (salt sensitivity), subsequent experiments are currently being conducted to explore further the role of nitric oxide in the systemic vascular adaptation to changes in sodium intake that will help bridge the gap between animal models and human subjects in our understanding of post-flight and bed rest-induced orthostasis.

Keywords: Orthostatic intolerance, Bed rest, Salt-sensitivity, Cardiac hemodynamic and structure

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