In addition to chronic airflow obstruction, patients with Chronic Obstructive Pulmonary Disease (COPD) suffer from skeletal muscle dysfunction which is a prominent and disabling feature and also an independent determinant of survival. Muscular impairment involves loss of muscle oxidative phenotype (OXPHEN: a slow-to-fast shift in fibre types and reduced oxidative capacity). Since hypoxia obviously is a key feature of COPD, the aim of this study is to elucidate the role of hypoxia in loss of muscle OXPHEN. Thus, OXPHEN and expression levels of its key regulators will be determined in the baseline biopsies for association with the degree of hypoxemia. In addition, expression levels of the key OXPHEN regulators will be measured in pre/post exercise biopsies.
Study Type
OBSERVATIONAL
Enrollment
13
The biopsy is performed on the vastus lateralis muscle at rest and 2 hours after an acute exercise, with a local anesthesia.
CHU de Saint-Etienne
Saint-Etienne, France
Level of expression of muscle messenger ribonucleic acid (mRNA) of HIF-1α and PGC-1α
Comparison of expression levels of Hypoxia-inducible Factors (HIF-1α) and Peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α), two OXYPHEN regulators, in muscle biopsy, between COPD patients with chronic hypoxemia and those with normoxemia
Time frame: Day 1
Type I muscle fibers
It is an indicator of the muscle phenotype (with a muscle biopsy). It used to compared the muscle phenotype in the 2 groups of patients. It is a percentage.
Time frame: Day 1
Oxidative enzyme capacity
It is an other indicator of the muscle phenotype (with a muscle biopsy). It used to compared the muscle phenotype in the 2 groups of patients.
Time frame: Day 1
Level of expression of muscle mRNA of HIF-1α after acute exercise
Comparison of response to acute exercise for expression level of HIF-1α (an OXYPHEN regulator) in muscle biopsy between the 2 groups.
Time frame: Day 1
Level of expression of muscle mRNA of PGC-1α after acute exercise
Comparison of response to acute exercise for expression level of PGC-1α (an OXYPHEN regulator) in muscle biopsy between the 2 groups.
Time frame: Day 1
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