Model analysis of oxygen transport and metabolism in skeletal muscle: responses to a change in energy demand

<p>The increase in skeletal muscle oxygen consumption (VO₂) at the onset of contraction is an indicator of the ability to do work. The VO₂ response to contraction (i.e., VO₂ kinetics) is determined by oxygen delivery (convective and diffusive) to tissue, oxygen utilization in muscle myocytes, and intracellular PO₂ (iPO₂). However, factors determining oxygen diffusion, including permeability-surface area (PS) and the blood-tissue O₂ gradient, are difficult to measure during the onset of contraction. Therefore, computational models of O₂ transport and metabolism in skeletal muscle can be used to elucidate underlying factors and predict the effects of alterations in oxygen transport and metabolism on VO₂ kinetics in skeletal muscle.</p><p>A computational model of O₂ transport and utilization in skeletal muscle, including changes in blood volume fractions at the onset of contraction, can be used to quantify changes in hemoglobin (Hb) and myoglobin (Mb) oxygenation in skeletal muscle at the onset of contraction. The model quantifies the increase in Mb deoxygenation where convective or diffusive oxygen delivery is limited, which increases the relative contribution of Mb to the total change in heme oxidation (measured by near-infrared spectroscopy) as compared to normal physiological conditions.</p><p>A computational model of O₂ transport and utilization, including anaerobic glycogenolysis, is used to investigate VO₂ and iPO₂ kinetics in response to submaximal and maximal contraction intensity in the canine gastrocnemius. The model is able to predict VO₂ kinetics for different blood flow (Q), contraction intensity, and arterial oxygen content in addition to quantifying the role of iPO₂ at higher contraction intensity. The model (A) predicts that PS is the major controller of oxygen diffusion and (B) quantifies the relationship between iPO₂ and contraction intensity, which depends on transport and metabolic properties of the muscle.</p><p>This model is also used to explore the effects of convective and diffusive limitations on VO₂ kinetics at the onset of contraction. The model (A) predicts a linear relationship between PS and Q and (B) quantifies the effects of convective, diffusive, and metabolic limitations on VO₂ kinetics in skeletal muscle.</p>

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Biomedical Engineering

Grantor dc:publisher

Case Western Reserve University School of Graduate Studies

Year dc:date

2013

Author dc:creator

• Spires, Jessica Rose

Contributors dc:contributor

• Saidel, Gerald

• Biomedical Engineering
• skeletal muscle
• oxygen diffusion
• convection
• contraction
• oxygenation
• hemoglobin
• myoglobin
• NIRS
• exercise
• bioenergetics
• glycolysis
• contraction intensity
• oxygen uptake kinetics
• oxygen utilization
• oxygen transport

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=case1365177364

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1365177364