Redox balance following magnetic stimulation training in the quadriceps of patients with severe COPD

Abstract

In severe COPD patients, oxidative stress, which is involved in their peripheral muscle dysfunction, increases in response to exercise. In this study, muscle oxidative stress was explored after quadriceps magnetic stimulation training. A randomized controlled study was conducted on very severe COPD patients, who underwent quadriceps magnetic stimulation training for 8 weeks. A control group was also studied. In both groups, vastus lateralis specimens were obtained before and after the 8-week period. Muscle protein carbonylation and nitration and antioxidant enzymes were determined using immunoblotting and proportions and sizes of type I and II fibres using immunohistochemistry. Compared to controls, magnetic stimulation muscle training did not modify redox balance, whilst inducing a significant increase in type I fibre sizes. In severe COPD patients, it is concluded that quadriceps magnetic stimulation training was a well-tolerated therapeutic intervention, which did not enhance muscle oxidative stress, while increasing the size of slow-twitch fibres.

Epigenetic regulation of muscle phenotype and adaptation: a potential role in COPD muscle dysfunction

“…These results have potential clinical implications in the management of patients with chronic lung diseases and muscle dysfunction including COPD, especially in the design of specific exercise training programs. Indeed, it has been clearly demonstrated that both the intensity and length of the training programs are of paramount importance to improve exercise capacity, muscle function, biology, and structure in those patients (17,21,58,68,80).…”

Role of Protein Carbonylation in Skeletal Muscle Mass Loss Associated with Chronic Conditions

“…Differences in the protein carbonyl content among several samples reflect their resistance or susceptibility to oxidative stress. In this regard, different studies from several groups including our own have demonstrated increases in the levels of protein carbonylation as well as identification using proteomics analyses in tissues under different conditions [14,15,16,17,18,19,23,30,31,32,34,35,36,40,41,61,62,63,64,65,66,67,68]. Indeed, protein oxidation has been shown to play a crucial role in the pathophysiology of multiple disorders such as degenerative diseases, aging, atherosclerosis, cancer, and skeletal muscle dysfunction associated with acute and chronic conditions [14,41,69,70].…”

“…For instance, the vastus lateralis muscle of patients with severe COPD consistently exhibits a slow-to-fast fiber type switch [18,19,123]. Nonetheless, in the same patients, a fast-to-slow fiber type transformation takes place in the diaphragm of patients with identical disease severity [14,23,88,123,124,125,126].…”

“…Oxidative stress, defined as the imbalance between oxidants and antioxidants in favor of the former (Figure 1), was shown to be a key contributing factor to the respiratory and limb muscle dysfunction of patients with COPD [14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30], muscles of animals with experimental cancer cachexia [31,32,33], and sepsis [34,35,36,37,38,39,40], and in elderly subjects [41,42,43]. High levels of oxidants may alter the function and structure of key cellular molecules such as proteins, DNA, and lipids, eventually leading to cellular injury and cell death (Figure 2) Moreover, protein oxidation including protein carbonylation was demonstrated to modify enzyme activity and DNA binding of transcription factors, while also rendering proteins more prone to proteolytic degradation (Figure 2) [44,45,46,47].…”

Skeletal Muscle Dysfunction: From Chronic Respiratory Disease to Critically Ill Patients

“…Oxidative stress, defined as the imbalance between oxidants and antioxidants, and as measured by several markers, such as protein oxidation and nitration and lipid peroxidation, has been consistently shown in blood and limb muscles of patients with severe COPD both at rest and after exercise 33,35,51,[54][55][56][57][58][59][60][61] . Importantly, oxidative stress markers were also shown to inversely correlate with several…”