TY - JOUR
T1 - Metabolic adaptations in skeletal muscle after 84 days of bed rest with and without concurrent flywheel resistance exercise
AU - Fernandez Gonzalo, Rodrigo
AU - Irimia, José M.
AU - Guerrero, Mario
AU - Rodriguez-Miguelez, Paula
AU - Cadefau, Joan A.
AU - Tesch, Per A.
AU - Cussó, Roser
N1 - Score=10
PY - 2017/1/18
Y1 - 2017/1/18
N2 - As metabolic changes in human skeletal muscle after long-term (simulated)
spaceflight are not well understood, this study examined the
effects of long-term microgravity, with and without concurrent resistance
exercise, on skeletal muscle oxidative and glycolytic capacity.
Twenty-one men were subjected to 84 days head-down tilt bed rest
with (BRE; n 9) or without (BR; n 12) concurrent flywheel
resistance exercise. Activity and gene expression of glycogen synthase,
glycogen phosphorylase (GPh), hexokinase, phosphofructokinase-
1 (PFK-1), and citrate synthase (CS), as well as gene expression
of succinate dehydrogenase (SDH), vascular endothelial growth factor
(VEFG), peroxisome proliferator-activated receptor gamma coactivator-
1 (PGC-1), and myostatin, were analyzed in samples from m.
vastus lateralis collected before and after bed rest. Activity and gene
expression of enzymes controlling oxidative metabolism (CS, SDH)
decreased in BR but were partially maintained in BRE. Activity of
enzymes regulating anaerobic glycolysis (GPh, PFK-1) was unchanged
in BR. Resistance exercise increased the activity of GPh.
PGC-1 and VEGF expression decreased in both BR and BRE.
Myostatin increased in BR but decreased in BRE after bed rest. The
analyses of these unique samples indicate that long-term microgravity
induces marked alterations in the oxidative, but not the glycolytic,
energy system. The proposed flywheel resistance exercise was effective
in counteracting some of the metabolic alterations triggered by
84-day bed rest. Given the disparity between gene expression vs.
enzyme activity in several key metabolic markers, posttranscriptional
mechanisms should be explored to fully evaluate metabolic adaptations
to long-term microgravity with/without exercise countermeasures
in human skeletal muscle.
AB - As metabolic changes in human skeletal muscle after long-term (simulated)
spaceflight are not well understood, this study examined the
effects of long-term microgravity, with and without concurrent resistance
exercise, on skeletal muscle oxidative and glycolytic capacity.
Twenty-one men were subjected to 84 days head-down tilt bed rest
with (BRE; n 9) or without (BR; n 12) concurrent flywheel
resistance exercise. Activity and gene expression of glycogen synthase,
glycogen phosphorylase (GPh), hexokinase, phosphofructokinase-
1 (PFK-1), and citrate synthase (CS), as well as gene expression
of succinate dehydrogenase (SDH), vascular endothelial growth factor
(VEFG), peroxisome proliferator-activated receptor gamma coactivator-
1 (PGC-1), and myostatin, were analyzed in samples from m.
vastus lateralis collected before and after bed rest. Activity and gene
expression of enzymes controlling oxidative metabolism (CS, SDH)
decreased in BR but were partially maintained in BRE. Activity of
enzymes regulating anaerobic glycolysis (GPh, PFK-1) was unchanged
in BR. Resistance exercise increased the activity of GPh.
PGC-1 and VEGF expression decreased in both BR and BRE.
Myostatin increased in BR but decreased in BRE after bed rest. The
analyses of these unique samples indicate that long-term microgravity
induces marked alterations in the oxidative, but not the glycolytic,
energy system. The proposed flywheel resistance exercise was effective
in counteracting some of the metabolic alterations triggered by
84-day bed rest. Given the disparity between gene expression vs.
enzyme activity in several key metabolic markers, posttranscriptional
mechanisms should be explored to fully evaluate metabolic adaptations
to long-term microgravity with/without exercise countermeasures
in human skeletal muscle.
KW - Microgravity
KW - glucose metabolism
KW - eccentric-overload
KW - spaceflight
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/21825447
U2 - 10.1152/japplphysiol.00521.2016
DO - 10.1152/japplphysiol.00521.2016
M3 - Article
SN - 8750-7587
VL - 122
SP - 96
EP - 103
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -