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Title: | Are ACE I/D and ACTN3 R577X polymorphisms associated with muscle function of young and older men, and frequent fallers? |
Authors: | McCauley, Tracey |
Keywords: | ACE AC1N3 Age Contractile properties Frequent fallers Muscle strength Muscle function |
Issue Date: | 2009 |
Publisher: | © Tracey McCauley |
Abstract: | Angiotensin Converting Enzyme (ACE) IID, and a actinin 3 (AC1N3) R577X
polymorphisms have been linked to the strength and power performance of elite athletes and
suggested to influence skeletal muscle function in the general popUlation. This research
investigated the association of these two candidate gene polymorphisms with the muscle
function of young and older men, and the distribution of these genotypes in frequent fallers
compared to controls. Muscle function measurements of young and older men included
isometric strength, absolute and relative isokinetic strength at high velocity (ratio of torque
at 2400 ·s"; torque at 30°·s") and the time course of an evoked twitch. Additionally body
composition was measured by skinfold thickness (young men) and DXA scanning (old men)
to estimate fat-free mass, an index of muscularity, and fat mass. ACE and AC1N3
genotypes were determined from whole blood samples using polymerase chain reaction, and
serum ACE activity using spectrophotometry. The gemtypes of frequent fallers referred to a
Falls Clinic were compared to a control group of healthy men. ACE genotype was not
associated with any measure of muscle function, including the time course of an evoked
twitch or absolute and relative high velocity torque, or body composition in these
populations (ANOVA, 0.12<P<0.97). Serum ACE activity appeared to be weakly associated
with knee extensor (R = 0.19, P = 0.07) and elbow flexor (R = 0.20, P = 0.06) isometric
strength in older men, and was negatively correlated with the relative torque at high velocity
(R = -0.23, P = 0.03). AC1N3 genotype was associated with fat mass in older men (P =
0.04), but was not associated with any measure of muscle function or muscularity (KruskalWaIIis,
0.26<P<0.95). Finally there was no apparent difference in the distribution of ACE
IID (r: = 0.54, P = 0.77) and AC1N3 RIX (r: = 0.76, P = 0.68) genotypes between frequent
fallers and controls. Any influence of these individual polymorphisms seems unlikely to be
of sufficient magnitude to produce genotype related differences in muscle function in young
or older free living UK Caucasian men. Serum ACE activity may have a small association
with the isometric and dynamic strength of older men. However, AC1N3 genotype was
associated with increased fat mass in XX individuals, that suggests this polymorphism may
have an association with the accumulation of body fat over the life span of older men. |
Description: | A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University |
URI: | https://dspace.lboro.ac.uk/2134/12930 |
Appears in Collections: | PhD Theses (Sport, Exercise and Health Sciences)
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