[HTML][HTML] Greater oxidative capacity in primary myotubes from endurance-trained women

TD Heden, TE Ryan, PJ Ferrara… - Medicine and science …, 2017 - ncbi.nlm.nih.gov
TD Heden, TE Ryan, PJ Ferrara, RC Hickner, PM Brophy, PD Neufer, JM McClung, K Funai
Medicine and science in sports and exercise, 2017ncbi.nlm.nih.gov
Purpose Exercise training promotes skeletal muscle mitochondrial biogenesis and an
increase in maximal oxygen consumption. Primary myotubes retain some metabolic
properties observed in vivo but it is unknown whether this includes exercise-induced
mitochondrial adaptations. The goal of this study was to test if primary myotubes from
exercise-trained women have higher mitochondrial content and maximal oxygen
consumption compared to untrained women. Methods Six trained and nine untrained …
Abstract
Purpose
Exercise training promotes skeletal muscle mitochondrial biogenesis and an increase in maximal oxygen consumption. Primary myotubes retain some metabolic properties observed in vivo but it is unknown whether this includes exercise-induced mitochondrial adaptations. The goal of this study was to test if primary myotubes from exercise-trained women have higher mitochondrial content and maximal oxygen consumption compared to untrained women.
Methods
Six trained and nine untrained Caucasian women participated in this study. Muscle biopsies from the vastus lateralis muscle of the right leg were obtained and primary muscle cells were isolated. Maximal respiration rates, mitochondrial mRNA and protein content, and succinate dehydrogenase activity were measured in skeletal muscle and primary myotubes from trained and untrained women.
Results
Trained women, compared to untrained women, had higher maximal whole-body oxygen consumption (+ 18%, P= 0.03), in vivo maximal skeletal muscle oxidative capacity measured with near infrared spectroscopy (+ 48%, P< 0.01), and maximal oxygen consumption in permeabilized muscle fibers (+ 38%, P= 0.02), which coincided with higher protein levels of muscle mitochondrial enzymes. Primary myotubes from trained women had higher maximal oxygen consumption (+ 38%, P= 0.03) suggesting that some elements of exercise-induced metabolic programming persists ex vivo. Consistent with this idea, myotubes from trained women had higher mRNA levels of transcriptional regulators of mitochondrial biogenesis in addition to higher protein levels of mitochondrial enzymes.
Conclusion
These data suggest the existence of an “exercise metabolic program”, where primary myotubes isolated from exercise-trained individuals exhibit greater mitochondrial content and oxidative capacity compared to untrained individuals. These myotubes may be a useful model to study molecular mechanisms relevant to exercise adaptations in human skeletal muscle.
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