Blood rheology on blood flow during plasmapheresis, plasma contraction, exercise, and chronic hypoxia in humans.
department or school: Health and Social Development, Faculty of (Okanagan)
department or school: Health and Exercise Sciences, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Steele, Andrew
issued: 2025-09-05T20:55:24Z
issued: 2025
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Blood rheology properties-including whole blood viscosity, plasma viscosity, and red blood cell (RBC) deformability and aggregation—are key regulators of blood flow and vascular function. Blood viscosity increases blood flow resistance but also contributes to shear stress, a key determinant of vascular resistance and diameter. RBC deformability and aggregation underlie the shear-thinning behavior of blood, allowing blood viscosity to adjust with changing shear rates. However, the extent to which blood rheology regulates blood flow in humans remains poorly understood. This dissertation aimed to examine how acute elevations in blood viscosity (Study 1) and RBC deformability (Studies 2 and 3) influence vascular perfusion and reactivity under distinct physiological and environmental conditions, including plasmapheresis, plasma contraction, exercise, and chronic hypoxia. In separate trials, study 1 induced hemoconcentration through plasma donation (via plasmapheresis) and diuresis (via oral furosemide) to assess its effects on brachial artery blood flow and reactive hyperemia flow-mediated dilation (RH-FMD). While increased blood viscosity did not alter brachial artery blood flow or RH-FMD, plasma donation and not diuresis enhanced microvascular function, as assessed by reactive hyperemia. Study 2 examined the impact of handgrip exercise and phosphodiesterase-5 inhibition (PDE5) with sildenafil citrate on RBC deformability, brachial artery blood flow, and cerebral blood flow (CBF). Exercise increased RBC deformability, and PDE5-i prolonged this elevated deformation; however, these changes did not affect basal CBF, brachial artery blood flow, or handgrip-induced exercise hyperemia. Study 3 evaluated the effects of pentoxifylline, a non-specific PDE inhibitor, on blood rheology, cardiac output, and CBF at high altitude. Chronic hypoxia increased blood viscosity and reduced RBC deformability, but pentoxifylline had no significant effect on blood rheology, CBF or cardiac out…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/92255
note: Blood rheology on blood flow during plasmapheresis, plasma contraction, exercise, and chronic hypoxia in humans. by Andrew Steele B.Sc., University of Alberta, 2017 M.Sc., University of Alberta, 2019 A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy in THE COLLEGE OF GRADUATE STUDIES (Kinesiology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) August 2025 © Andrew Steele, 2025 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies, the dissertation entitled: Blood rheology on blood flow during plasmapheresis, plasma contraction, exercise, and chronic hypoxia in humans. submitted by Andrew Steele in partial fulfilment of the requirements for the degree of Doctor of Philosophy Examining Committee: Dr. Philip Ainslie – School of Health and Exercise Sciences Supervisor Dr. Glen Foster – School of Health and Exercise Sciences Supervisory Committee Member Dr. Ryan Hoiland – Department of Cellular and Physiological Sciences Supervisory Committee Member Dr. Christopher West – Department of Cellular and Physiological Sciences University Examiner Dr. Michael Simmonds – Griffith University External Examiner iii Abstract Blood rheology properties-including whole blood viscosity, plasma viscosity, and red blood cell (RBC) deformability and aggregation—are key regulators of blood flow and vascular function. Blood viscosity increases blood flow resistance but also contributes to shear stress, a key determinant of vascular resistance and diameter. RBC deformability and aggregation underlie the shear-thinning behavior of blood, allowing blood viscosity to adjust with changing shear rates. However, the extent to which blood rheology regulates blood flow in humans remains poorly understood. This dissertation aimed to examine how acute elevations in blood viscosity (Study 1) and RBC deformability (Studies 2 and 3) influence vascular perfusion and reactivity under distinct physiol…
has type: Thesis/Dissertation
date issued: 2025-09
is shown at: 10.14288/1.0450054
language: eng
degree discipline: Kinesiology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Ainslie, Philip N., 1974-
type: Text
identifier URI: http://hdl.handle.net/2429/92255