Oxidative Stress and Total Phenolics Concentration in COPD Patients-The Effect of Exercises: A Randomized Controlled Trial

A Network Meta-Analysis on the Effects of Different Exercise Types in Patients With COPD

BACKGROUND

This study aimed to compare and rank the effects of aerobic exercise, resistance training, endurance training, and high-intensity interval training in COPD by network meta-analysis.

METHODS

PubMed, Cochrane, Embase, and the Web of Science were searched to identify randomized controlled trials that investigated the effects of exercise training on COPD. The search period began on the date of database establishment and ended on April 8, 2023. Two reviewers independently screened the retrieved articles, extracted relevant data, and assessed the risk of bias in the included studies. Network meta-analysis was performed by using statistical software.

RESULTS

This study included a total of 27 studies that involved 1,415 subjects. The network meta-analysis findings indicated that high-intensity interval training was the most-effective intervention for improving 6-min walk distance with a surface under the cumulative ranking curve score of 87.68%. In addition, high-intensity interval training showed the highest efficacy in improving FEV1 with a surface under the cumulative ranking curve score of 73.17%, FEV1/FVC with a surface under the cumulative ranking curve score of 79.52%, and St. George Respiratory Questionnaire score with a surface under the cumulative ranking curve score of 73.88%. Conversely, endurance training was found to be the most effective for ameliorating FVC with a surface under the cumulative ranking curve score of 73.39%.

CONCLUSIONS

The findings of this study suggest that high-intensity interval training may be more effective than endurance exercise, resistance exercise, and aerobic exercise in improving the 6-min walk distance, FEV1, FEV1/FVC, and St. George Respiratory Questionnaire scores in patients with COPD. In addition, endurance training may be better than resistance exercise, aerobic exercise, and high-intensity interval training in improving FVC in patients with COPD. However, due to the limited number of studies conducted on high-intensity interval training, more high-quality randomized controlled trials are required to verify these conclusions.

Oxidative stress: roles in skeletal muscle atrophy

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.

Changes in Blood Markers of Oxidative Stress, Inflammation and Cardiometabolic Patients with COPD after Eccentric and Concentric Cycling Training

Chronic obstructive pulmonary disease (COPD) patients manifest muscle dysfunction and impaired muscle oxidative capacity, which result in reduced exercise capacity and poor health status. This study examined the effects of 12-week eccentric (ECC) and concentric (CONC) cycling training on plasma markers of cardiometabolic health, oxidative stress, and inflammation in COPD patients. A randomized trial in which moderate COPD was allocated to ECC (n = 10; 68.2 ± 10.0 year) or CONC (n = 10; 71.1 ± 10.3 year) training groups. Participants performed 12-week ECC or CONC training, 2-3 sessions per week, 10 to 30 min per session. Before and after training, peak oxygen consumption, maximal power output (VO_2peak and PO_max), and time-to-exhaustion (TTE) tests were performed. Plasma antioxidant and oxidative markers, insulin resistance, lipid profile, and systemic inflammation markers were measured before and after training at rest. VO_2peak, PO_max and TTE remained unchanged after ECC and CONC. CONC induced an increase in antioxidants (p = 0.01), while ECC decreased antioxidant (p = 0.02) markers measured at rest. CONC induced lesser increase in oxidative stress following TTE (p = 0.04), and a decrease in insulin resistance (p = 0.0006) compared to baseline. These results suggest that CONC training induced an increase in insulin sensitivity, antioxidant capacity at rest, and lesser exercise-induced oxidative stress in patients with moderate COPD.

Assessment of Oxidative Stress Indices and Total Phenolics Concentrations in Obese Adult Women-The Effect of Training with Supplemental Oxygen: A Randomized Controlled Trial

Background: The aim of this study was to determine the effect of using an oxygen-enriched breathing mixture during controlled physical training on blood oxidative stress parameters and total phenolics (TP) concentrations in obese adult women. Methods: A prospective randomized controlled trial study included 60 women aged 19−68 with BMIs greater than 30 kg/m2. Patients were randomly assigned to the study group (n = 30), which received additional intervention in supplementing the breathing mixture with oxygen at the flow of 6 L/min during training sessions, and the control group (n = 30). At the beginning and at the end of the study, anthropometric assessments (height and weight and BMI) and blood tests (CRP, FRAP, TBARS, TP, BAC, and La) were performed. For each patient, an individual endurance training plan was established on a cycloergometer, including 12 training units, based on a cardiopulmonary exercise test (CPET). Results: A decrease in blood TBARS concentration was observed in each study group. For the control group, the change was more remarkable, and the difference between the groups was significant at (p < 0.05; ES: 0.583). Training with the oxygen breathing mixture increased blood concentrations of TP, while a decrease in TP in blood was observed in the group without oxygen supplementation during physical training. The difference in the responses between the groups was significant at (p < 0.05; ES: 0.657) Conclusions: Increasing the concentration of oxygen in the respiratory mixture under conditions of increased exercise was shown to be safe because it did not exacerbate oxidative stress in the obese group.

Effect of Endurance Training in COPD Patients Undergoing Pulmonary Rehabilitation: A Meta-Analysis

Background

The efficacy of endurance training (ET) on patients with chronic obstructive pulmonary disease (COPD) has been controversial. This study was aimed at meta-analyzing the effect of ET in COPD patients undergoing pulmonary rehabilitation.

Methods

The literature retrieval was performed in databases to screen relevant literature. Inclusion criteria were as follows: (1) subjects—COPD patients; (2) inclusion of interventional and control groups; (3) intervention measures—the interventional group received whole-body ET and other lung rehabilitation training, while the control group did not receive intervention or other lung rehabilitation training; (4) outcome indicators which included at least one of the following—6MWD, modified Medical Research Council questionnaire (mMRC), and COPD Assessment Test (CAT); and (5) study type—randomized controlled trials (RCTs). The Cochrane risk-of-bias tool was used to assess the risk of bias. The chi-square test was used to evaluate the magnitude of heterogeneity. Subgroup analysis was used to explore the source of heterogeneity. A funnel plot and Egger's test were used to evaluate publication bias.

Results

The 6MWD in the ET group was significantly higher than that in the control group (MD = 47.20, 95% CI [28.60, 65.79], P < 0.00001). Significant heterogeneity (P < 0.00001, I² = 76%) without publication bias (P > 0.05) was noted. Subgroup analysis showed that the 6MWD of the ET group was significantly larger than that of the control group without heterogeneity (P = 0.63, I² = 0%; P = 0.59, I² = 0%) in both the no training subgroup (MD = 79.26, 95% CI [72.69, 85.82], P < 0.00001) and other rehabilitation training group (MD = 23.64, 95% CI [6.70, 40.57], P = 0.006). The mMRC score (MD = −0.72, 95% CI [-1.09, -0.34], P = 0.002) and CAT (MD = −6.07, 95% CI [-7.28, -4.87], P < 0.00001) of the ET group were significantly lower than those of the control group. There was no heterogeneity (P = 0.32, I² = 15%; P = 0.16, I² = 41%).

Conclusion

ET can improve patients' motor function and reduce dyspnea. ET might be incorporated as an important part of lung rehabilitation training.