Antioxidant Treatment of Muscle Wasting and Fatigue in Tumor-Bearing Mice DISSERTATION ...

112 Pages·2013·1.19 MB·English

Antioxidant Treatment of Muscle Wasting and Fatigue in Tumor-Bearing Mice

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy
in the Graduate School of The Ohio State University

By
Yvonne Yumiko Clark
Graduate Program in Nursing

The Ohio State University
2013

Dissertation Committee:
Donna O McCarthy, PhD Advisor
Loren E Wold, PhD
Jodi C. McDaniel, PhD
Laura A. Szalacha, PhD
Copyright by
Yvonne Yumiko Clark
2013
Abstract

Purpose: Fatigue is the most common and distressing symptom reported by cancer
patients, significantly reducing quality of life. While the mechanisms of cancer-related
fatigue (CRF) are poorly understood, evidence indicates that pro-inflammatory cytokines
and reactive oxygen species, produced by the tumor and/or host, alter muscle metabolism
to cause muscle wasting and cardiac dysfunction. Symptoms of muscle wasting and
cardiac dysfunction are weakness and decreased effort tolerance, similar to patients with
CRF. Ubiquinol, an endogenously produced, lipid soluble antioxidant, protects against
lipid peroxidation to cellular lipid membranes, proteins and DNA, and regenerates active
forms of other antioxidants such as vitamins C and E. The purpose of this study was to
determine if treatment with ubiquinol, might preserve muscle mass, improve cardiac
function, and reduce fatigue in an animal model of CRF. The following hypotheses were
tested in mice bearing the colon26 (C26) adenocarcinoma: 1. Ubiquinol will reduce the
expression of biomarkers of muscle protein degradation and increase protein synthesis in
the gastrocnemius and cardiac muscles of tumor-bearing mice; 2. Ubiquinol will increase:
(a) muscle mass, (b) fore-limb grip strength, (c) in vivo cardiac function, and (d)
voluntary running activity (VRA) in tumor-bearing mice and; 3. Ubiquinol will not affect
tumor growth.
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Method: Eight week old adult female CD2F1 mice were acclimated to running wheels
and grip strength 1 week prior to being inoculated with the tumor cells. Half of the
control and half of the tumor bearing mice received ubiquinol 500 mg/kg/day in their
drinking water. VRA and grip strength were measured on days 0, 8, 14 and 17 of tumor
growth. Cardiac function was measured by echocardiography on day 18 or 19 after which
the mice were euthanized. The heart and gastrocnemius muscles were weighed and
normalized to body weight. Serum levels of proinflammatory cytokines were measured
by ELISA. Oxidative stress was measured in skeletal and cardiac muscle homogenates.
Skeletal and cardiac muscle expression of genes reflecting muscle inflammation and
biomarkers associated with muscle metabolism were determined using real time-PCR.
Results: Tumor growth induced loss of muscle mass and decreased VRA and grip
strength. Tumor growth also increased serum and muscle levels of pro-inflammatory
cytokines, oxidative stress in cardiac muscle, altered cardiac function and biomarkers
associated with muscle metabolism in skeletal muscle. Echocardiography revealed a
diastolic dysfunction in the tumor-bearing mice. Treatment with ubiquinol did not alter
levels of proinflammatory cytokines in serum and skeletal and cardiac muscle, oxidative
stress in cardiac muscle, biomarkers associated with muscle metabolism, cardiac
function, VRA or grip strength in the tumor-bearing mice, but did increase skeletal
muscle mass.
Conclusion: These data confirm prior studies indicating tumor growth alone affects
cardiac function, which could contribute to CRF. Because ubiquinol improved muscle
mass without affecting measures of fatigue and weakness, inflammation, cardiac function
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or muscle metabolism, we conclude that antioxidant treatment alone is not likely to
reverse CRF. These data also suggest that skeletal muscle wasting may not be a major
factor in reduced physical activity and weakness associated with CRF.

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Dedication

This is dedicated to everyone who supported and helped me along my journey. This
includes my children: Monica, Maria and Naman; my parents: Joshua and Kimie Bacon;
my family members: to include Gloria, Sophia, Kimie and Dale Jr.; and a great friend:
Shiron Devere Jones

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Acknowledgments

I would like to thank my committee members: Dr Donna McCarthy, Dr Loren
Wold, Dr Jodi McDaniel and Dr Laura Szalacha for their help and support during this
process. I would like to thank Dr Loren Wold for being a co-sponsor on my Kirschstein
Award and his help in educating me and completing the cardiac piece of my research. Dr
Wold’s staff: Matthew, Dane and Ray were wonderful, helpful and always available if I
had questions or needed assistance. I would like to especially acknowledge Raymond
Devine for taking lots of time to complete and read the echocardiography measurement
on my mice and always finding articles or giving insight on certain aspects of my
research. I would like to thank Runfeng Jing for the training I received in Dr McCarthy’s
lab and especially Danielle Crawford who came in at odd hours to educate and train me
on the various laboratory techniques and equipment. Trina Wemlinger, manager of the
Clinical Research Center laboratory, deserves a special recognition for coming in after
hours and for all her assistance with my ELISAs. Words cannot describe the appreciation
and thanks I have for my advisor/mentor Dr Donna McCarthy. Her support, guidance and
training over the past 4 years allowed me to accomplish my goals in research and even
surpass them. She was always willing to go the extra mile for me. I will never forget, and
be forever grateful to Dr McCarthy for all that she has done for me. Thanks you to Dr
Priscilla Koeplin for your help in editing this dissertation and for all your kind words and
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support during this process. I also would like to acknowledge my family: Monica, Maria,
Naman, Amari, Johnny, Gloria, Sophia, Kimie, Dale Jr., and my best friend Shiron for all
of their support over the years and for giving me strength to continue.

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Vita

1985................................................................A.D.N. Sinclair Community College
2000................................................................B.S. N. Andrews University
2004................................................................M.S. Wright State University
2009 to present ..............................................College of Nursing, The Ohio State
University

Fields of Study

Major Field: Nursing

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Table of Contents

Abstract ............................................................................................................................... ii
Dedication ........................................................................................................................... v
Acknowledgments.............................................................................................................. vi
Vita ................................................................................................................................... viii
Fields of Study ................................................................................................................. viii
Table of Contents ............................................................................................................... ix
List of Tables ...................................................................................................................... x
List of Figures .................................................................................................................... xi
Chapter 1: Introduction ...................................................................................................... 1
Chapter 2: Review of Literature ....................................................................................... 11
Chapter 3: Methods ........................................................................................................... 29
Chapter 4: Results ............................................................................................................. 39
Chapter 5: Discussion ....................................................................................................... 56
References ......................................................................................................................... 74

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