Skeletal Muscle Dysfunction in Patients with Chronic Obstructive Pulmonary Disease

Decreased Tongue Strength is Related to Skeletal Muscle Mass in COPD Patients

Dysphagia is frequently observed in patients with chronic obstructive pulmonary disease (COPD). Decreased tongue strength is one of the causes of dysphagia, and it is often observed in patients with sarcopenia. Sarcopenia is also frequently observed in COPD patients. We hypothesized that tongue strength is lower in COPD patients compared to normal subjects. This was a single-center, observational, cross-sectional study. Maximum tongue pressure (MTP) was measured in 27 patients with COPD and 24 age-matched control subjects. We also evaluated handgrip strength, gait speed, and appendicular skeletal muscle mass to define subjects as having sarcopenia. We used bioelectrical impedance analysis to assess body composition. The eating assessment test-10 was used to diagnose dysphagia. MTP was significantly lower in COPD patients than in control subjects (33.8 ± 8.4 vs 38.0 ± 5.3; p = 0.032). All measures of muscle and fat free body mass, handgrip strength, and gait speed were also significantly lower in COPD patients compared to control subjects (p < 0.01). The prevalence of sarcopenia in COPD patients was higher than that in control subjects (6/27 versus 0/24; p = 0.007), but the prevalence of dysphagia was not different between groups (COPD: 5/27, versus control: 1/24; p = 0.112). MTP was moderately correlated with skeletal muscle mass index (r = 0.56, p = 0.003) and handgrip strength (r = 0.43, p = 0.027) in COPD patients. Tongue strength was lower in COPD patients compared to normal subjects, and decreased tongue strength may be correlated with sarcopenia in COPD patients.

Validation of Clinical Characteristics and Effectiveness of Pulmonary Rehabilitation in a COPD Population with Discrepancy between Exercise Tolerance and FEV1

This study’s objective was to examine the characteristics of patients with chronic obstructive pulmonary disease (COPD) presenting with various exercise tolerance levels. A total of 235 patients with stable COPD were classified into 4 groups: (1) LoFlo + HiEx—patients with a six-minute walking distance (6MWD) ≥350 m and percentage of predicted forced expiratory volume in 1 s (%FEV_1.0) <50%; (2) HiFlo + HiEx—patients with a 6MWD ≥350 m and a %FEV_1.0 ≥50%; (3) LoFlo + LoEx—patients with a 6MWD < 350 m and %FEV_1.0 < 50%; and (4) HiFlo + LoEx—patients with a 6MWD <350 m and %FEV_1.0 ≥ 50%. Aspects of physical ability in the HiFlo + LoEx group were significantly lower than those in the HiFlo + HiEx group. The HiFlo + LoEx group was characterized by a history of hospitalization for respiratory illness within the past year, treatment with at-home oxygen therapy, and lacking daily exercise habits. Following three months of pulmonary rehabilitation, the LoFlo + HiEx group significantly improved in the modified Medical Research Council dyspnea score, maximum gait speed, and 6MWD, while the HiFlo + LoEx group significantly improved in the percentage of maximal expiratory pressure, maximum gait speed, 6MWD, incremental shuttle walking distance, and St. George’s Respiratory Questionnaire score. The HiFlo + LoEx group had the greatest effect of three-month pulmonary rehabilitation compared to other groups.

A systematic review and meta-analysis of the effectiveness of virtual reality as an exercise intervention for individuals with a respiratory condition

BACKGROUND

Respiratory diseases impose an immense health burden worldwide and affect millions of people on a global scale. Reduction of exercise tolerance poses a huge health issue affecting patients with a respiratory condition, which is caused by skeletal muscle dysfunction and weakness and by lung function impairment. Virtual reality systems are emerging technologies that have drawn scientists' attention to its potential benefit for rehabilitation.

METHODS

A systematic review and meta-analysis following the PRISMA guidelines was performed to explore the effectiveness of virtual reality gaming and exergaming-based interventions on individuals with respiratory conditions.

RESULTS

Differences between the virtual reality intervention and traditional exercise rehabilitation revealed weak to insignificant effect size for mean heart rate (standardized mean difference, SMD = 0.17; p = 0.002), peak heart rate (SMD = 0.36; p = 0.27), dyspnea (SMD = 0.32; p = 0.13), and oxygen saturation SpO2 (SMD = 0.26; p = 0.096). In addition, other measures were collected, however, to the heterogeneity of reporting, could not be included in the meta-analysis. These included adherence, enjoyment, and drop-out rates.

CONCLUSIONS

The use of VRS as an intervention can provide options for rehabilitation, given their moderate effect for dyspnea and equivalent to weak effect for mean and maximum peak HR and SpO2. However, the use of virtual reality systems, as an intervention, needs further study since the literature lacks standardized methods to accurately analyze the effects of virtual reality for individuals with respiratory conditions, especially for duration, virtual reality system type, adherence, adverse effects, feasibility, enjoyment, and quality of life.

Association Between the Predictors of Functional Capacity and Heart Rate Off-Kinetics in Patients with Chronic Obstructive Pulmonary Disease

Background

The heart rate (HR) kinetics as well as other predictors of functional capacity such as the Chronic Obstructive Pulmonary Disease (COPD) Assessment Test (CAT), the Duke Activity Status Index (DASI) and the handgrip strength (HGS) represent important tools in assessing the impact of COPD on exercise performance and health status of individuals with COPD.

Purpose

To verify the relationship between functional capacity, measured using the six-minute walking test (6MWT), with the HR off-kinetics, HGS and the DASI and CAT scores.

Methods

For this cross-sectional study, 29 subjects with COPD underwent body composition, pulmonary function and cardiac function tests. Subsequently, the DASI and CAT questionnaires and HGS test were performed. The beat-to-beat R-R intervals (IRR) were collected in rest, during the test and in recovery after the 6MWT. The HR off-kinetics was obtained during a 360-second period in post-exercise recovery through the HR mono-exponential decay.

Results

Moderate correlations were observed between: 1) walked distance (WD) in the 6MWT and the CAT and DASI scores (r= −0.58, p=0.001 and r= 0.58, p=0.001, respectively); 2) WD and HGS (r=0.37, p=0.05); 3) and WD and HR off-kinetics (τ; r= −0.54, p=0.002 and MRT; r= −0.55, p=0.002, respectively).

Conclusion

The 6MWT performance is a direct measurement to evaluate functional capacity. Additionally, it is related to other direct and indirect markers for functional evaluation in patients with COPD. These results suggest the application of these tools in clinical practice, based on the accessibility, non-invasive character and easy applicability of these methods.

Sabinene Prevents Skeletal Muscle Atrophy by Inhibiting the MAPK-MuRF-1 Pathway in Rats

Chrysanthemum boreale Makino essential oil (CBMEO) has diverse biological activities including a skin regenerating effect. However, its role in muscle atrophy remains unknown. This study explored the effects of CBMEO and its active ingredients on skeletal muscle atrophy using in vitro and in vivo models of muscle atrophy. CBMEO reversed the size decrease of L6 myoblasts under starvation. Among the eight monoterpene compounds of CBMEO without cytotoxicity for L6 cells, sabinene induced predominant recovery of reductions of myotube diameters under starvation. Sabinene diminished the elevated E3 ubiquitin ligase muscle ring-finger protein-1 (MuRF-1) expression and p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylations in starved myotubes. Moreover, sabinene decreased the increased level of reactive oxygen species (ROS) in myotubes under starvation. The ROS inhibitor antagonized expression of MuRF-1 and phosphorylation of MAPKs, which were elevated in starved myotubes. In addition, levels of muscle fiber atrophy and MuRF-1 expression in gastrocnemius from fasted rats were reduced after administration of sabinene. These findings demonstrate that sabinene, a bioactive component from CBMEO, may attenuate skeletal muscle atrophy by regulating the activation mechanism of ROS-mediated MAPK/MuRF-1 pathways in starved myotubes, probably leading to the reverse of reduced muscle fiber size in fasted rats.

Association between CT-Measured Abdominal Skeletal Muscle Mass and Pulmonary Function

A relationship between lung function and sarcopenia has been suggested. This study aimed to evaluate the association between lung function and abdominal skeletal muscle mass, as measured by computed tomography (CT). The clinical records of 1907 subjects (1406 males, mean age 53.1 ± 9.2 years), who underwent routine health check-ups, including spirometry and abdominal CT, were retrospectively reviewed. The CT-measured skeletal muscle index (SMI_CT, cm²/(kg/m²) was defined as the skeletal muscle area of the third lumbar vertebrae (L3) level that is normalized by the body mass index. The mean values of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) gradually increased as the SMI_CT quartiles increased (all p for trend < 0.05). The proportions of subjects with less than 80% of the predicted FVC (%) and predicted FEV1 (%) significantly decreased as the SMI_CT quartiles increased (all p for trend < 0.05). The β regression coefficients for FVC and FEV1 significantly increased as the SMI_CT quartiles increased after adjusting for other confounding variables (p for trend < 0.05). This study showed that abdominal muscle mass, which was precisely measured by CT, independently affected lung function proportionally after adjusting for confounding factors in relatively healthy adults.

Validation of Korean Version of the London Chest Activity of Daily Living Scale in Patients With Chronic Obstructive Pulmonary Disease

Objective

To translate the English version of the London Chest Activity of Daily Living scale (LCADL) into a Korean version and to determine the reliability and validity of the Korean version in patients with chronic obstructive pulmonary disease (COPD).

Methods

The English version of LCADL was translated into Korean and back-translated into English. Subsequently, the back-translated version was reviewed and compared with the original, and thus the final K-LCADL was obtained. To evaluate the validation of the K-LCADL, patients simultaneously completed a pulmonary function test, a 6-Minute Walk Test (6MWT), and questionnaires, including the modified Medical Research Council (mMRC) dyspnea scale, the Korean version of the St. George's Respiratory Questionnaire (K-SGRQ), the Korean version of the COPD Assessment Test (K-CAT), and the Korean version of the EuroQoL-5 Dimensions (K-EQ-5D). To assess test-retest reliability, the K-LCADL was again administered to the same patients within 2 weeks from initial assessment.

Results

A total of 94 patients participated in the present study. The total K-LCADL score was positively correlated with the K-SGRQ (r=0.802, p<0.001), the mMRC dyspnea scale (r=0.603, p<0.001), and the K-CAT score (r=0.714, p<0.001), and negatively correlated with the K-EQ-5D (r=−0.764, p<0.001), 6MWT (r=−0.635, p<0.001), forced expiratory volume in one second 1 (r=−0.416, p=0.002), and forced vital capacity (r=−0.397, p=0.023). Intraclass correlation coefficient of the K-LCADL was 0.951 (p<0.001).

Conclusion

The K-LCADL is a reliable and valid questionnaire for evaluating limitation of activities of daily living in patients with COPD.