Deterioration of Limb Muscle Function during Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Aging enhances pro-atrogenic gene expression and skeletal muscle loss following respiratory syncytial virus infection

Aging and many age-related health conditions are associated with skeletal muscle loss. Furthermore, older adults are more susceptible to severe respiratory infections, which can in turn lead to muscle wasting. The mechanisms by which respiratory viral infection can impact skeletal muscle in older adults are not well understood. We determined the effects of acute infection with respiratory syncytial virus (RSV) on the lung and skeletal muscle of aged mice. RSV infection caused more severe disease in aged mice with enhanced weight loss, reduced feeding, higher viral load, and greater airway inflammation. Aged but not young mice showed decreased leg muscle weight at the peak of illness and decreased size of leg muscle fibers. Aged mice increased muscle-specific expression of atrophy-promoting enzymes (Atrogin-1 and MuRF-1) and failed to increase the rate of muscle protein synthesis during RSV infection. In aged mice, the changes in Atrogin-1 and MuRF-1 gene expression in skeletal muscle correlated with IL-6 levels in the lungs. These findings indicate that RSV infection of aged mice provides a model for studying the diverse adverse systemic consequences of respiratory viral infections on health and wellbeing in older adults.

Shear wave elastography, as a feasible tool, can be used to reflect the lower limb dysfunction in patients with chronic obstructive pulmonary disease?

To explore the additional value of shear wave elastography (SWE) in chronic obstructive pulmonary disease (COPD) patients. Ultrasound elastography of the rectus femoris and patellar tendon was performed to determine the mean elasticity index (SWEmean) of the rectus femoris (SWERF) and patellar tendon (SWEPT) in 56 patients with COPD and 53 healthy controls. Clinical tests included the COPD Assessment Test (CAT), the dyspnea index score (modified British Medical Research Council (mMRC)score), the Five-Repetition Sit-to-Stand Test(5STS) and the Six-Minute Walk Test (6MWT). We compared differences in SWEmean between healthy controls and COPD patients while describing the correlation between SWEmean and clinical tests in COPD patients. Both the intra-observer and inter-observer repeatability of SWE performance were excellent (all correlation coefficients > 0.75; p < 0.05). There was a statistically significant difference between healthy controls and COPD patients in the SWERF and SWEPT between healthy controls and COPD patients (p < 0.001). The COPD patients had smaller SWERF and larger SWEPT than healthy controls. The SWERF was positively correlated with the 6MWT (r = 0.591, p < 0.001), and negatively related to the mMRC (r = - 0.794, p < 0.001), CAT (r = - 0.894, p < 0.001) and 5STS (r = - 0.928, p < 0.001). But the SWEPT was positively related to the 6MWT (r = 0.269, p < 0.05), mMRC (r = 0.398, p < 0.05), CAT (r = 0.377, p < 0.05) and 5STS (r = 0.332, p < 0.05). SWEmean of COPD patients was statisticant, different from that of healthy controls, and associated with clinical tests. SWE was a simple and feasible tool for reflecting the lower limb dysfunction in patients with COPD.

Skeletal Muscle Function in Relation to COPD Severity and Its Predictive Significance for Disease Progression

Purpose

To compare skeletal muscle function levels in different COPD severities and explore their relationship with COPD severity and progression.

Patients and Methods

The study included COPD patients from the First People's Hospital of Shuangliu District, Chengdu between May 2021 and May 2022, categorized into mild, moderate, severe and very severe groups based on FEV1%. Skeletal muscle function (quadriceps strength, respiratory muscle strength, 6MWD) was compared among these groups. Patients were followed up to assess disease progression, and logistic regression was used to analyze the predictive value of skeletal muscle function for COPD progression.

Results

Among the 400 subjects, respiratory muscle strength, quadriceps strength, and 6MWD were all higher in the nonsmoking group than in the smoking group, with the mild group better than the moderate group, the moderate group better than the severe group, males stronger than females, the MMRC score ≤ 2 group better than the >2 group, and strength greater in the age ≤ 70 group than in the age >70 group. The mild group had a higher 6MWD than the moderate group, the moderate group was better than the severe group, non-smokers had a higher 6MWD than smokers, and the difference between males and females was greater with statistical significance. There are differences in quadriceps strength, respiratory strength, and 6MWD within the progression group. Logistic regression analysis showed that respiratory muscle strength, quadriceps strength, 6MWD, and COPD severity were risk factors for COPD progression (P < 0.05).

Conclusion

COPD patients show skeletal muscle dysfunction that worsens with disease severity. Respiratory muscle strength, quadriceps strength, 6MWD, and COPD severity predict COPD prognosis.

The Role of Diaphragmatic Ultrasound in Identifying Sarcopenia in COPD Patients: A Cross-Sectional Study

Background/Aim

Chronic obstructive pulmonary disease (COPD) is often complicated by sarcopenia, a condition of reduced muscle mass and function that adversely affects quality of life, lung function, and exacerbation rates. Ultrasonography could be an effective tool for detecting sarcopenia, notably by assessing diaphragmatic function, which may indicate muscle health in COPD patients. This study aims to evaluate the effectiveness of diaphragmatic ultrasound in detecting sarcopenia among COPD patients.

Materials and Methods

Thirty-five patients with COPD, with a forced expiratory volume in one second (FEV1) between 30% and 80%, were consecutively enrolled in this cross-sectional and double-blind study. Sarcopenia was defined using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. Muscle mass was assessed with bioelectrical impedance analysis (BIA), muscle strength was assessed using the handgrip test and physical performance was assessed using a 4-meter gait speed test. Pulmonary function tests (PFT) (including maximum inspiratory pressure-MIP and maximum expiratory pressure-MEP) were performed. Diaphragm excursion and thickness at residual volume, functional residual capacity, and total lung capacity were measured using ultrasound. The diaphragm thickening fraction was calculated during normal (TF) and deep breathing (TLC-TF).

Results

Seventeen of 35 patients (48.6%) were found to be sarcopenic. Diaphragm thickness did not show significant variation between the groups. Both TF (27.43%) and TLC-TF (39.7%) were found to be lower in the sarcopenic group (p<0.05). The diaphragmatic excursion in the sarcopenic group was found to be 1.38 cm (p=0.078). There was no difference in median MIP and MEP values between the groups.

Conclusion

Diaphragmatic TF may be a valuable tool for detecting sarcopenia in COPD patients, which may vary independently of PFTs. This study highlights TF as a potential auxiliary measure, but further research with larger sample sizes and additional parameters is needed to confirm its clinical utility.

Current perspectives on the rehabilitation of COPD patients with comorbidities

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is frequently accompanied by a variety of comorbidities, complicating management and rehabilitation efforts. Understanding this interplay is crucial for optimizing patient outcomes.

AREAS COVERED

This review, based on the MEDLINE, Embase and Cochrane Library databases, summarizes the main research on the rehabilitation of patients with COPD, with an emphasis on relevant comorbidities, such as cardiovascular diseases, pulmonary hypertension, lung cancer, metabolic, musculoskeletal, and gastrointestinal disorders. anxiety/depression and cognitive disorders. The study highlights the importance of pre-participation assessments, ongoing monitoring and personalized rehabilitation programs. A review includes a comprehensive literature search to assess the scientific evidence on these interventions and their impact.

EXPERT OPINION

The integration of cardiorespiratory rehabilitation program is essential for improving physical capacity and quality of life in COPD patients with comorbidities. While existing studies highlight positive outcomes, challenges such as interdisciplinary collaboration and access to rehabilitation services remain. Future strategies must prioritize personalized and integrated approaches programs combining pharmacological optimization and a close monitoring during cardiopulmonary rehabilitation to significantly reduce hospital readmissions and mortality, even in patients with complex multimorbidities. Continued research is necessary to refine rehabilitation protocols and better understand the complexities of managing COPD alongside cardiac conditions.

A 7-point evidence-based care discharge protocol for patients hospitalized for exacerbation of COPD: consensus strategy and expert recommendation

Acute exacerbations of COPD (ECOPD) are an important event in the life of a COPD patient as it causes significant deterioration of physical, mental, and social health, hastens disease progression, increases the risk of dying and causes a huge economic loss. Preventing ECOPD is therefore one of the most important goals in the management of COPD. Before the patient is discharged after hospitalization for ECOPD, it is crucial to offer an evidence-based care bundle protocol that will help minimize the future risk of readmissions and death. To develop the content of this quality care bundle, an Expert Working Group was formed, which performed a systematic review of literature, brainstormed, and debated on key clinical issues before arriving at a consensus strategy that could help physicians achieve this goal. A 7-point consensus strategy was prepared, which included: (1) enhancing awareness and seriousness of ECOPD, (2) identifying patients at risk for future exacerbations, (3) optimizing pharmacologic treatment of COPD, (4) identifying and treating comorbidities, (5) preventing bacterial and viral infections, (6) pulmonary rehabilitation, and (7) palliative care. Physicians may find this 7-point care bundle useful to minimize the risk of future exacerbations and reduce morbidity and mortality.

DKK3 as a diagnostic marker and potential therapeutic target for sarcopenia in chronic obstructive pulmonary disease

Sarcopenia, characterized by the progressive loss of muscle mass and function, significantly affects patients with chronic obstructive pulmonary disease (COPD) and worsens their morbidity and mortality. The pathogenesis of muscle atrophy in patients with COPD involves complex mechanisms, including protein imbalance and mitochondrial dysfunction, which have been identified in the muscle tissues of patients with COPD. DKK3 (Dickkopf-3) is a secreted glycoprotein involved in the process of myogenesis. However, the role of DKK3 in the regulation of muscle mass is largely unknown. This study investigated the role of DKK3 in COPD-related sarcopenia. DKK3 was found to be overexpressed in cigarette smoking-induced muscle atrophy and in patients with COPD. Importantly, plasma DKK3 levels in COPD patients with sarcopenia were significantly higher than those without sarcopenia, and plasma DKK3 levels could effectively predict sarcopenia in patients with COPD based on two independent cohorts. Mechanistically, DKK3 is secreted by skeletal muscle cells that acts in autocrine and paracrine manners and interacts with the cell surface-activated receptor cytoskeleton-associated protein 4 (CKAP4) to induce mitochondrial dysfunction and myotube atrophy. The inhibition of DKK3 by genetic ablation prevented cigarette smoking-induced skeletal muscle dysfunction. These results suggest that DKK3 is a potential target for the diagnosis and treatment of sarcopenia in patients with COPD.

Multifaceted associations between walking performance, physical fitness, extremity function, health status, and depression in individuals with COPD

BACKGROUND/OBJECTIVE(S)

Chronic obstructive pulmonary disease (COPD) can precipitate a deterioration of an individual's physical performance and overall health. Evidence suggests that, along with pulmonary functions, several other factors are related to the significant impairment of walking performance in individuals with COPD. This study compared the depressive symptoms, health status, upper and lower extremity functions, and peak oxygen uptake (VO2peak) in a group of individuals with COPD based on walking performance using a cutoff distance of 350 m in the six-minute walking test (6MWT). The study also investigated the associations between these factors and walking performance.

MATERIALS AND METHODS

Participants performed the 6MWT according to the guidelines and were classified into high (>350 m; n = 40) or low (<350 m; n = 30) walking performance groups according to distance. The forced expiratory volume (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio were recorded. Participants completed the Patient Health Questionnaire-9 (PHQ-9), St. George's Respiratory Questionnaire (SGRQ), and the Upper and Lower Extremity Functional Index (UEFI/LEFI). Predicted VO2peak was measured using the Duke Activity Status Index (DASI).

RESULTS

Seventy participants with a mean age of 63 ± 11 years (20% female) were enrolled in this study. Patients with high walking performance demonstrated significantly better health status than those with low walking performance (SGRQ: 49 ± 25 vs. 56 ± 21, p = 0.03). Participants with low walking performance had lower predicted VO2peak compared to their higher performing counterparts (p = 0.002). The overall model was significant (F(8, 61) = 7.48, p = 0.0006), with PHQ-9, SGRQ, UEFI/LEFI, VO2peak, and FEV1/FVC explaining approximately 49.5% of the variance in the 6MWT distance.

CONCLUSION

This study shed light on the association of depressive symptoms, health status, extremity function, and VO2peak with walking performance, providing valuable insights that may impact the management and care of individuals with COPD.

Temporal Dynamics of Cardiovascular Risk in Patients with Chronic Obstructive Pulmonary Disease During Stable Disease and Exacerbations: Review of the Mechanisms and Implications

Introduction

Exacerbations of chronic obstructive pulmonary disease (COPD) are risk factors for severe cardiovascular (CV) events, with the risk remaining significantly elevated long after the symptomatic phase of the exacerbation. The pathophysiology underpinning the relationship between acute events of both COPD and CV diseases has been understudied. Our objectives were to review the mechanisms by which COPD exacerbations increase the risk of CV events and understand the temporality of this risk.

Methods

A pragmatic and targeted literature review was conducted with a focus on identifying recent, high-impact papers up to June 2023, guided by insights from subject matter experts including pulmonologists and cardiologists.

Results

A substantial number of inter-related mechanisms underpin the spiral of anatomical and functional deterioration of lung and heart affecting COPD patients during stable state. In turn, an exacerbation of COPD may trigger a CV event, during and beyond the symptomatic phase, due to ventilation/perfusion mismatch, oxygen supply-demand imbalance, oxidative stress, systemic inflammation, hypercoagulable state, dynamic hyperinflation, pulmonary hypertension, and sympathetic activation. However, no study was identified that explored the mechanisms by which an exacerbation confers a sustained risk of CV event.

Conclusion

While our review identified multiple dynamic and interacting pathophysiological mechanisms during and after an exacerbation of COPD that contribute to increasing the risk of a wide range of cardiac events, little is known regarding the precise long-term mechanisms after acute exacerbation to explain the persistent increased CV event risk beyond the symptomatic phase. The temporal changes in static and dynamic substrates need further characterization to better understand the different risk factors and risk periods for a CV event following the onset of an exacerbation. Moreover, guideline-directed cardiopulmonary therapies should be implemented at every opportunity; preventing exacerbations and intensively treating traditional CV risk factors should be a focus in COPD management.

Cognitive interference of respiratory versus limb muscle dual tasking in healthy adults

Background

Inspiratory threshold loading (ITL) and associated dyspnoea have been shown to interfere with cognition during cognitive-motor dual tasking. However, ITL has not been compared with another rhythmic muscle activity, such as lower limb pedalling. While ITL has been shown to interfere with cognition, the mechanism of the prefrontal cortex (PFC) during ITL or other rhythmical muscle dual tasking, has not been elucidated. Given the cognitive interference that arises during ITL, we hypothesise that ITL cognitive-motor dual tasking will result in greater cognitive decrements and increased PFC activity compared with the pedalling cognitive-motor dual task.

Methods

30 healthy participants (16 females; median age 23 (interquartile range 23-24) years) were recruited. They performed five 3-min tasks in a single visit in a random order: single tasks were ITL, pedalling and Stroop task and dual tasks were ITL-Stroop and pedalling-Stroop. Participant's PFC activity was assessed bilaterally using functional near-infrared spectroscopy throughout each task. Single- and dual-task cognitive performance was evaluated by measuring Stroop task reaction time and accuracy. Dyspnoea and rating of perceived exertion were evaluated at the end of each task.

Results

ITL-Stroop resulted in greater impairments in reaction time (p<0.001), accuracy (p<0.01) and increased medial/dorsolateral PFC activity (p≤0.006) than pedalling-Stroop. ITL-Stroop elicited greater Borg dyspnoea and rating of perceived exertion than pedalling-Stroop (p<0.001), despite pedalling-Stroop having a greater heart rate response (p<0.001).

Conclusion

The heightened cognitive decrements, perceptual response and PFC activity suggest that inspiratory muscle loading and its accompanied dyspnoea results in greater cognitive interference than rhythmic pedalling.

Succinate dehydrogenase-complex II regulates skeletal muscle cellular respiration and contractility but not muscle mass in genetically induced pulmonary emphysema

Reduced skeletal muscle mass and oxidative capacity coexist in patients with pulmonary emphysema and are independently associated with higher mortality. If reduced cellular respiration contributes to muscle atrophy in that setting remains unknown. Using a mouse with genetically induced pulmonary emphysema that recapitulates muscle dysfunction, we found that reduced activity of succinate dehydrogenase (SDH) is a hallmark of its myopathic changes. We generated an inducible, muscle-specific SDH knockout mouse that demonstrates lower mitochondrial oxygen consumption, myofiber contractility, and exercise endurance. Respirometry analyses show that in vitro complex I respiration is unaffected by loss of SDH subunit C in muscle mitochondria, which is consistent with the pulmonary emphysema animal data. SDH knockout initially causes succinate accumulation associated with a down-regulated transcriptome but modest proteome effects. Muscle mass, myofiber type composition, and overall body mass constituents remain unaltered in the transgenic mice. Thus, while SDH regulates myofiber respiration in experimental pulmonary emphysema, it does not control muscle mass or other body constituents.

Exploring Balance Impairment and Determinants in Chronic Obstructive Pulmonary Disease: A Comparative Study with Healthy Subjects

Background: Many pulmonary and extrapulmonary factors may impair balance in patients with chronic obstructive pulmonary disease (COPD), but the determinants of this impairment are still debated. The primary aim was to compare both balance-related and independent variables that may affect balance with healthy subjects. The secondary aim was to investigate the potential determinants of balance in patients with COPD. Methods: This comparative study recruited 23 patients with COPD and 23 age- and comorbidity-matched healthy subjects. Participants were assessed regarding demographic and clinical data, "Postural Stability Test" (PST), "Limits of Stability Test" (LOST), "Clinical Test of Sensory Integration of Balance" (CTSIB), pulmonary function, respiratory and peripheral muscle strength, functional capacity, and cognitive function. Results: There were significant differences in all outcome measures assessing balance, pulmonary function, respiratory muscle strength, peripheral muscle strength, and functional capacity, but not cognitive function, in the COPD group compared to the healthy group (p < 0.05). The PST had a significant and strong correlation with maximal inspiratory pressure (MIP) (r = -0.630, p = 0.001) and a significant and moderate correlation with m. quadriceps strength and 6 min walk test (6MWT) distance (r = -0.472, p = 0.023; r = -0.496, p = 0.016; respectively). MIP, m. quadriceps strength, and 6MWT distance were independent predictors to explain the PST with an R2 = 0.336 (p = 0.004). Conclusions: The present study revealed that balance is impaired in adults with COPD, even if compared with age- and comorbidity-matched healthy subjects. Assessing and improving balance and its determinants, inspiratory and peripheral muscle strength, and functional capacity may be important for fall prevention and disease management in patients with COPD.

Acute ischemic colitis complicating an exacerbation of chronic obstructive pulmonary disease: A case report of gut-lung crosstalk

Acute ischemic colitis is a pathology as frequent as it is serious and requires urgent management. It's often occurring in a context of particular thromboembolic or hypovolemic risk, but certain clinical situations are not commonly known to provide mesenteric ischemia. Herein, we report the case of a 47-year-old man who presented with a severe acute colitis occurring in the course of acute exacerbation of a chronic obstructive pulmonary diseases with maintained stability of hemodynamic state. The diagnosis of acute ischemic colitis complicating an exacerbation of chronic obstructive pulmonary diseases was made. A clinical and biological improvement quickly marked the patient's condition after the management of the respiratory problem.

Nutritional Strategies for Muscle Atrophy: Current Evidence and Underlying Mechanisms

Skeletal muscle can undergo detrimental changes in various diseases, leading to muscle dysfunction and atrophy, thus severely affecting people's lives. Along with exercise, there is a growing interest in the potential of nutritional support against muscle atrophy. This review provides a brief overview of the molecular mechanisms driving skeletal muscle atrophy and summarizes recent advances in nutritional interventions for preventing and treating muscle atrophy. The nutritional supplements include amino acids and their derivatives (such as leucine, β-hydroxy, β-methylbutyrate, and creatine), various antioxidant supplements (like Coenzyme Q10 and mitoquinone, resveratrol, curcumin, quercetin, Omega 3 fatty acids), minerals (such as magnesium and selenium), and vitamins (such as vitamin B, vitamin C, vitamin D, and vitamin E), as well as probiotics and prebiotics (like Lactobacillus, Bifidobacterium, and 1-kestose). Furthermore, the study discusses the impact of a combined approach involving nutritional support and physical therapy to prevent muscle atrophy, suggests appropriate multi-nutritional and multi-modal interventions based on individual conditions to optimize treatment outcomes, and enhances the recovery of muscle function for patients. By understanding the molecular mechanisms behind skeletal muscle atrophy and implementing appropriate interventions, it is possible to enhance the recovery of muscle function and improve patients' quality of life.

Musculoskeletal crosstalk in chronic obstructive pulmonary disease and comorbidities: Emerging roles and therapeutic potentials

Chronic Obstructive Pulmonary Disease (COPD) is a multifaceted respiratory disorder characterized by progressive airflow limitation and systemic implications. It has become increasingly apparent that COPD exerts its influence far beyond the respiratory system, extending its impact to various organ systems. Among these, the musculoskeletal system emerges as a central player in both the pathogenesis and management of COPD and its associated comorbidities. Muscle dysfunction and osteoporosis are prevalent musculoskeletal disorders in COPD patients, leading to a substantial decline in exercise capacity and overall health. These manifestations are influenced by systemic inflammation, oxidative stress, and hormonal imbalances, all hallmarks of COPD. Recent research has uncovered an intricate interplay between COPD and musculoskeletal comorbidities, suggesting that muscle and bone tissues may cross-communicate through the release of signalling molecules, known as "myokines" and "osteokines". We explored this dynamic relationship, with a particular focus on the role of the immune system in mediating the cross-communication between muscle and bone in COPD. Moreover, we delved into existing and emerging therapeutic strategies for managing musculoskeletal disorders in COPD. It underscores the development of personalized treatment approaches that target both the respiratory and musculoskeletal aspects of COPD, offering the promise of improved well-being and quality of life for individuals grappling with this complex condition. This comprehensive review underscores the significance of recognizing the profound impact of COPD on the musculoskeletal system and its comorbidities. By unravelling the intricate connections between these systems and exploring innovative treatment avenues, we can aspire to enhance the overall care and outcomes for COPD patients, ultimately offering hope for improved health and well-being.

The Impact of Exercise Training and Supplemental Oxygen on Peripheral Muscles in Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

OBJECTIVE

Exercise training is a cornerstone of the treatment of chronic obstructive pulmonary disease, whereas the related interindividual heterogeneity in skeletal muscle dysfunction and adaptations are not yet fully understood. We set out to investigate the effects of exercise training and supplemental oxygen on functional and structural peripheral muscle adaptation.

METHODS

In this prospective, randomized, controlled, double-blind study, 28 patients with nonhypoxemic chronic obstructive pulmonary disease (forced expiratory volume in 1 second, 45.92% ± 9.06%) performed 6 wk of combined endurance and strength training, three times a week while breathing either supplemental oxygen or medical air. The impact on exercise capacity, muscle strength, and quadriceps femoris muscle cross-sectional area (CSA) was assessed by maximal cardiopulmonary exercise testing, 10-repetition maximum strength test of knee extension, and magnetic resonance imaging, respectively.

RESULTS

After exercise training, patients demonstrated a significant increase in functional capacity, aerobic capacity, exercise tolerance, quadriceps muscle strength, and bilateral CSA. Supplemental oxygen affected significantly the training impact on peak work rate when compared with medical air (+0.20 ± 0.03 vs +0.12 ± 0.03 W·kg -1 , P = 0.047); a significant increase in CSA (+3.9 ± 1.3 cm 2 , P = 0.013) was only observed in the training group using oxygen. Supplemental oxygen and exercise-induced peripheral desaturation were identified as significant opposing determinants of muscle gain during this exercise training intervention, which led to different adaptations of CSA between the respective subgroups.

CONCLUSIONS

The heterogenous functional and structural muscle adaptations seem determined by supplemental oxygen and exercise-induced hypoxia. Indeed, supplemental oxygen may facilitate muscular training adaptations, particularly in limb muscle dysfunction, thereby contributing to the enhanced training responses on maximal aerobic and functional capacity.

Impact of acute exacerbations of COPD on patients' health status beyond pulmonary function: A scoping review

This scoping review summarized the evidence regarding the impact of acute exacerbations of COPD (AECOPD) on patients' health status beyond pulmonary function. PubMed, Embase, and Web of Science were searched. Prospective cohort studies assessing the health status of patients with COPD in a stable phase of the disease and after a follow-up period (where at least one AECOPD occurred) were included. An integrated assessment framework of health status (i.e., physiological functioning, complaints, functional impairment, quality of life) was used. Twenty-two studies were included. AECOPD acutely affected exercise tolerance, quadriceps muscle strength, physical activity levels, symptoms of dyspnoea and fatigue, and impact of the disease. Long-term effects on quadriceps muscle strength, symptoms of dyspnoea and depression, and quality of life were found. Repeated exacerbations negatively impacted the fat-free mass, levels of dyspnoea, impact of the disease and quality of life. Conflicting evidence was found regarding the impact of repeated exacerbations on exercise tolerance and physical activity levels. AECOPD have well-established acute and long-term adverse effects on health status beyond pulmonary function; nevertheless, the recovery trajectory and the impact of repeated exacerbations are still poorly studied. Further prospective research is recommended to draw firm conclusions on these aspects.

Performance-based outcome measures to assess functionality in hospitalised patients with COPD exacerbations: a systematic review of the measurement properties

INTRODUCTION

Hospitalised patients with exacerbations of COPD (ECOPD) may have physical and functional impairments that impact morbidity and readmission. Therefore, it is crucial to properly identify reduced functionality in these patients to support a personalised rehabilitation. The objective of this study is to summarise and compare the measurement properties of functionality performance-based outcome measures for hospitalised patients with ECOPD.

METHODS

A systematic review based on the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) was performed. The PubMed, Embase, PEDro and Cochrane databases were searched using terms related to functionality, hospitalised patients with ECOPD and measurement properties. Studies were selected and extracted by two researchers. The COSMIN Risk of Bias checklist was applied to assess the methodological quality of the studies and measurement property results were compared with the criteria for good measurement properties. Quality of evidence was graded using a modified Grades of Recommendation, Assessment, Development and Evaluation approach.

RESULTS

13 studies were included with nine outcome measures, namely the 6-min pegboard ring test, the de Morton mobility index, the incremental shuttle walk test (ISWT), the 6-min walk test (6MWT), maximum inspiratory pressure (MIP), the Berg balance scale, 4-m gait speed, handgrip strength and the 6-min stepper test. Construct validity was rated as sufficient, except for the ISWT. Responsiveness, assessed only for MIP, was considered insufficient and measurement errors for the ISWT and 6MWT were insufficient, with a very low quality of evidence for all measurement properties.

CONCLUSION

Measurement properties of performance-based outcome measures to assess functionality in patients hospitalised with ECOPD are still scarce, with very low evidence supporting validity and a lack of evidence of responsiveness and reliability. Further studies are needed to address this topic and guide assertive and personalised management.

Long-Term Clinical Outcomes of Patients with Chronic Obstructive Pulmonary Disease with Sarcopenia

BACKGROUND AND OBJECTIVE

Sarcopenia with muscle wasting and weakness is a common occurrence among patients with chronic obstructive pulmonary disease (COPD). We aimed to evaluate the clinical outcomes of sarcopenia in patients with COPD.

METHODS

We reviewed the electronic medical records of 71 patients with COPD between 1 January 2012, and 31 December 2018. We longitudinally analyzed clinical outcomes in patients with COPD with and without sarcopenia.

RESULTS

Compared to the non-sarcopenia group COPD, the sarcopenia group showed a higher rate of acute exacerbation events of COPD (AE COPD, 84.6% vs. 31.0%, p = 0.001), all-cause mortality (30.8% vs. 5.2%, p = 0.022), and pneumonia occurrence per year (median [first quartile-third quartile]; 0.2 [0.0-1.6] vs. 0.0 [0.0-0.2], p = 0.025). Sarcopenia was an independent risk factor for AE COPD in Cox regression analysis (hazard ratio, 5.982; 95% confidence interval, 1.576-22.704). Hand grip strength was associated with the COPD Assessment Test (CAT) score and annual Charlson's comorbidity index score change. Total skeletal muscle mass index (SMMI) was associated with the modified medical research council dyspnea scale score, CAT score, body mass index, airflow obstruction, dyspnea, and exercise (BODE) index, and alanine transaminase. Trunk SMMI was significantly associated with AE COPD, while appendicular SMMI was associated with BODE index and annual intensive care unit admissions for AE COPD.

CONCLUSIONS

Sarcopenia is associated with clinical prognosis, pneumonia occurrence, and the acute exacerbation of COPD requiring intensive care in patients with COPD. Therefore, it is important to carefully monitor sarcopenia development as well as recommend appropriate exercise and nutritional supplementation in patients with COPD.

Impaired Skeletal Muscle in Patients with Stable Chronic Obstructive Pulmonary Disease (COPD) Compared with Non-COPD Patients

Purpose

This study was designed to investigate the differences in skeletal-muscle atrophy between patients with stable chronic obstructive pulmonary disease (COPD) and healthy controls; associated factors were also considered. The study comprised selected residents of communities near the First Affiliated Hospital of Soochow University in Suzhou City, East China.

Patients and Methods

Included in this study were 123 COPD patients and 60 controls. All patients completed spirometry as well as examinations to determine their functional exercise capacity, body composition, and handgrip strength (HGS).

Results

COPD patients had less fat-free mass (FFM), a lower FFM index (FFMI), and a lower 6-min walking distance (6MWD) compared with controls (P = 0.007, P = 0.020, and P < 0.001, respectively) (FFMI: 17.59 ± 1.83 vs 18.34 ± 1.64). The HGS of these patients was also lower compared with that of controls (32.88 ± 7.84 vs 35.48 ± 7.42), and HGS tended toward statistical significance (P = 0.064, respectively). In multivariate analysis, age (β = -0.107, P < 0.001), gender (β = 0.212, P < 0.001), body mass index (BMI) (β = 0.462, P < 0.001), FEV1% (β = 0.108, P = 0.009), and calf circumference (CC) (β = 0.457, P < 0.001) were significantly associated with FFMI.

Conclusion

Impaired skeletal muscle mass was more common in COPD patients than in controls. Multiple regression analysis showed that CC may be used to detect the degree of impairment, particularly by health-care providers working outside of the hospital.

Effects of a Single Session of Systemic Vibratory Therapy on Flexibility, Perception of Exertion and Handgrip Strength in Chronic Obstructive Pulmonary Disease Individuals: A Quasi-Experimental Clinical Trial

BACKGROUND

Whole-body vibration exercises (WBVE), that are generated in systemic vibratory therapy (SVT), may benefit individuals with chronic obstructive pulmonary disease (COPD). This study evaluated acute effects of SVT on the flexibility, on the perception of exertion to perform the anterior trunk flexion (ATF), and on the handgrip strength (HG).

METHODS

Thirty-eight individuals, separated into two groups, performed a single session of SVT (five bouts, 25 Hz, 2.5 of amplitude) on a side-alternating vibrating platform (SAVP), in two postures: sitting (Sitting group-SitG, n = 21) or standing (Stand group-StandG, n = 17). In both positions, the feet were on the base of the SAVP. The HG and the AFT were performed before and after the session, and the perception of effort (RPE) was measured during the ATF.

RESULTS

The ATF in the SitG (p ≤ 0.05) and in the StandG (p ≤ 0.05) was significantly improved, but in the comparison between both groups, no significant reduction was found (p = 0.14). The RPE was not influenced by the session. A significant increase of the HG in StandG post session (33.49 ± 10.30 kgf) p = 0.03 was found, but not in the SitG (p = 0.12) or between the two groups (p = 0.55).

CONCLUSIONS

SVT, in a single acute session, would be capable of promoting some functional benefits for the COPD individuals without altering the perception of exertion to perform the ATF.

TRIAL REGISTRATION

49219115.3.0000.5259, RBR-72dqtm.

Shear Wave Elastography for Detecting Calf Muscle Stiffness: An Effective Tool for Assessing Sarcopenia

OBJECTIVES

To explore the feasibility of shear wave elastography for evaluating sarcopenia.

METHODS

The shear wave velocities (SWV) of the tibialis anterior, medial gastrocnemius, and soleus were measured in 130 subjects in the Second Affiliated Hospital of Fujian Medical University from January 2021 to June 2022. Consistency was evaluated in 20 cases using the intraclass correlation coefficient. According to the 2019 Asian Working Group for Sarcopenia（AWGS） diagnostic criteria, the patients were divided into a healthy and a sarcopenia group. The differences in SWV between the two groups were compared, and their correlation between calf muscles and muscle mass, grip strength, and pace were analyzed. The diagnostic cutoff value of calf muscle SWV for sarcopenia was obtained using receiver operating characteristic (ROC) curves, and the diagnostic efficacy of different ROC curves was compared.

RESULTS

The SWV inter-group and intra-group correlation coefficients of the three lower limbs muscles were all greater than 0.85. Moreover, the corresponding SWV in the sarcopenia group were significantly smaller than those in the healthy control group (P < .05). Further, SWV were positively correlated with the appendicular skeletal muscle mass index (ASMI), grip strength, and gait speed. Finally, the SWV of the anterior tibialis and medial gastrocnemius muscles were 3.02 and 2.26 m/s, respectively, and their diagnostic efficacy for sarcopenia did not differ significantly (Z = 0.190, P = .8497).

CONCLUSION

SWE can be used to detect the hardness of the anterior tibialis and medial gastrocnemius, calculate their muscle mass as an effective tool to evaluate sarcopenia.

Respiratory and peripheral muscle strength influence recovery of exercise capacity after severe exacerbation of COPD? An observational prospective cohort study

BACKGROUND

Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) have decreased exercise tolerance, which may persist for months. In this context, little is known about the associations between muscle strength and recovery of exercise capacity.

OBJECTIVE

To assess whether respiratory and peripheral muscle strength influence recovery of exercise capacity in patients hospitalized due to AECOPD.

METHODS

Twenty-seven AECOPD patients (aged 69 ± 7 years, 56% male) were included. The following assessments were performed within 24 to 72 h of hospital admission: (i) respiratory muscle strength, measured by maximal inspiratory and expiratory pressures (MIP and MEP); (ii) peripheral muscle strength, assessed by handgrip and quadriceps muscle strength; and (iii) exercise capacity, measured by 6-min walking distance (6MWD). The 6MWD was reassessed 30 days later to determine the recovery of exercise capacity.

RESULTS

After 30 days, while 63% of the patients showed clinically important improvement in the 6MWD (recovery ≥ 30 m), 37% showed no change (recovery < 30 m). During hospital stay, the non-recovered group had lower quadriceps muscle strength compared to the recovered group (15 ± 5 vs. 22 ± 6 kgf; P = 0.006), with no significant difference for MIP, MEP and handgrip strength. Only quadriceps muscle strength was associated with recovery of exercise capacity (r = 0.56; P = 0.003).

CONCLUSION

AECOPD patients with quadriceps muscle weakness during hospitalization have poor recovery of exercise capacity after 30 days. This finding suggests the importance of early rehabilitation to improve quadriceps strength and accelerate functional recovery after AECOPD.

Impaired muscle stem cell function and abnormal myogenesis in acquired myopathies

Skeletal muscle possesses a high plasticity and a remarkable regenerative capacity that relies mainly on muscle stem cells (MuSCs). Molecular and cellular components of the MuSC niche, such as immune cells, play key roles to coordinate MuSC function and to orchestrate muscle regeneration. An abnormal infiltration of immune cells and/or imbalance of pro- and anti-inflammatory cytokines could lead to MuSC dysfunctions that could have long lasting effects on muscle function. Different genetic variants were shown to cause muscular dystrophies that intrinsically compromise MuSC function and/or disturb their microenvironment leading to impaired muscle regeneration that contributes to disease progression. Alternatively, many acquired myopathies caused by comorbidities (e.g., cardiopulmonary or kidney diseases), chronic inflammation/infection, or side effects of different drugs can also perturb MuSC function and their microenvironment. The goal of this review is to comprehensively summarize the current knowledge on acquired myopathies and their impact on MuSC function. We further describe potential therapeutic strategies to restore MuSC regenerative capacity.

Determinants of acute care discharge in adults with chronic obstructive pulmonary disease

CONCLUSIONS

In adults with COPD basic mobility scores on the AM-PAC "6-clicks" measure completed at discharge had the best sensitivity and specificity for predicting discharge to home and need for rehab services.

Prevalence of sarcopenia in patients with COPD through different musculature measurements: An updated meta-analysis and meta-regression

Aim

Chronic obstructive pulmonary disease (COPD) patients vary widely in terms of the prevalence of sarcopenia, which is partially attributed to differences in diagnostic criteria and disease severity. There are several different musculature measurements that are used to quantify sarcopenia. This study included published literature for meta-analysis to assess the sarcopenia prevalence in COPD patients and correlate the disease with the clinical characteristics of such patients.

Methods

A comprehensive review of the English and Chinese literature on sarcopenia prevalence in COPD patients was conducted using electronic databases such as China National Knowledge Infrastructure (CNKI), Web of Science, Cochrane Library, EMBASE, PubMed, and Wanfang. Two researchers analyzed the studies for Newcastle-Ottawa Scale. The software Stata 11.0 was employed for the analysis of the acquired data. The standard mean differences method was utilized for the estimation and quantification of the effect size. Furthermore, a fixed- or random-effects model was employed for conducting a combined analysis.

Results

In total, 56 studies were included as per the specific inclusion criteria. The resulting data of the assessed COPD patients in this research indicated a 27% prevalence of sarcopenia. Further analysis of subgroups was executed per disease severity, ethnicity, diagnostic criteria, gender, and age. Per these findings, increased disease severity elevated the prevalence of sarcopenia. The Latin American and Caucasian populations indicated an increased prevalence of sarcopenia. In addition, the prevalence of sarcopenia was related to diagnostic criteria and definition. Male COPD patients had a higher prevalence of sarcopenia than female COPD patients. COPD patients with an average age greater than 65 had a slightly higher prevalence of sarcopenia. COPD patients with comorbid sarcopenia had poorer pulmonary function, activity tolerance, and clinical symptoms than patients with COPD alone.

Conclusion

Sarcopenia prevalence is high (27%) in COPD patients. In addition, these patients had worse pulmonary function and activity tolerance compared to patients without sarcopenia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=367422, identifier CRD42022367422.

Acute effects of NIV on peripheral muscle function and aerobic performance in patients with chronic obstructive pulmonary disease: a pilot study

Background

Non-invasive ventilation (NIV) reduces respiratory load and demands on peripheral muscles.

Methods

This study aims to evaluate the acute effects of bi-level NIV on peripheral muscle function during isokinetic exercise and aerobic performance in chronic obstructive pulmonary disease (COPD) patients. This is a pilot crossover study performed with a non-probabilistic sample of 14 moderate to very severe COPD patients. Procedures carried out in two days. Dyspnea, quality of life, lung function, respiratory muscle strength, functional capacity (6-min walk test—6MWT), and isokinetic assessment of the quadriceps were assessed. Blood samples (lactate, lactate dehydrogenase, and creatine kinase concentration) were also collected. Right after, NIV was performed for 30 min (bi-level or placebo, according to randomization) followed by new blood sample collection, 6MWT, and isokinetic dynamometer tests. Before and after evaluations, the subjective perception of dyspnea and fatigue in the lower limbs was quantified. After a wash-out period of seven days, participants returned, and all assessments were performed again.

Results

NIV showed improvements in perceived exertion and dyspnea after isokinetic exercise (p < 0.02 and p < 0.05, respectively).

Conclusions

NIV improves the perception of dyspnea and fatigue during the isokinetic exercise.

Influence of COPD systemic environment on the myogenic function of muscle precursor cells in vitro

Background:

Loss of muscle mass and function are well-recognized systemic manifestations of chronic obstructive pulmonary disease (COPD). Acute exacerbations, in turn, significantly contribute to upgrade these systemic comorbidities. Involvement of myogenic precursors in muscle mass maintenance and recovery is poorly understood. The aim of the present study was to investigate the effects of the vascular systemic environment from stable and exacerbated COPD patients on the myogenic behavior of human muscle precursor cells (MPC) in vitro.

Methods:

Serum from healthy controls and from stable and exacerbated COPD patients (before and after Methylprednisolone treatment) was used to stimulate human MPC cultures. Proliferation analysis was assessed through BrdU incorporation assays. MPC differentiation was examined through real-time RT-PCR, western blot and immunofluorescence analysis.

Results:

Stimulation of MPCs with serum obtained from stable COPD patients did not affect myogenic precursor cell function. The vascular systemic environment during an acute exacerbation exerted a mitotic effect on MPCs without altering myogenic differentiation outcome. After Methylprednisolone treatment of acute exacerbated COPD patients, however, the mitotic effect was further amplified, but it was followed by a deficient differentiation capacity. Moreover, these effects were prevented when cells were co-treated with the glucocorticoid receptor antagonist Mifepristone.

Conclusion:

Our findings suggest that MPC capacity is inherently preserved in COPD patients, but is compromised after systemic administration of MP. This finding strengthens the concept that glucocorticoid treatment over the long term can negatively impact myogenic stem cell fate decisions and interfere with muscle mass recovery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02203-6.

Impaired regenerative capacity contributes to skeletal muscle dysfunction in chronic obstructive pulmonary disease

Locomotor skeletal muscle dysfunction is a relevant comorbidity of chronic obstructive pulmonary disease (COPD) and is strongly associated with worse clinical outcomes including higher mortality. Over the last decades, a large body of literature helped characterize the process, defining the disruptive muscle phenotype caused by COPD that involves reduction in muscle mass, force-generation capacity, fatigue-tolerance, and regenerative potential following injury. A major limitation in the field has been the scarcity of well-calibrated animal models to conduct mechanistic research based on loss- and gain-of-function studies. This article provides an overall description of the process, the tools available to mechanistically investigate it, and the potential role of mitochondrially driven metabolic signals on the regulation muscle regeneration after injury in COPD. Finally, a description of future avenues to further expand on the area is proposed based on very recent evidence involving mitochondrial metabolic cues affecting myogenesis.

Effects of Cigarette Smoke on Adipose and Skeletal Muscle Tissue: In Vivo and In Vitro Studies

Chronic obstructive pulmonary disease (COPD), often caused by smoking, is a chronic lung disease with systemic manifestations including metabolic comorbidities. This study investigates adaptive and pathological alterations in adipose and skeletal muscle tissue following cigarette smoke exposure using in vivo and in vitro models. Mice were exposed to cigarette smoke or air for 72 days and the pre-adipose cell line 3T3-L1 was utilized as an in vitro model. Cigarette smoke exposure decreased body weight, and the proportional loss in fat mass was more pronounced than the lean mass loss. Cigarette smoke exposure reduced adipocyte size and increased adipocyte numbers. Adipose macrophage numbers and associated cytokine levels, including interleukin-1β, interleukine-6 and tumor necrosis factor-α were elevated in smoke-exposed mice. Muscle strength and protein synthesis signaling were decreased after smoke exposure; however, muscle mass was not changed. In vitro studies demonstrated that lipolysis and fatty acid oxidation were upregulated in cigarette smoke-exposed pre-adipocytes. In conclusion, cigarette smoke exposure induces a loss of whole-body fat mass and adipose atrophy, which is likely due to enhanced lipolysis.

SWEmean of Quadriceps, a Potential Index of Complication Evaluation to Patients with Chronic Obstructive Pulmonary Disease

Purpose

To develop a potential quadriceps' index of complication evaluation for patients with chronic obstructive pulmonary disease (COPD) which is simple, convenient, and quantifiable.

Patients and Methods

We conducted a prospective study of 59 patients with COPD and 56 healthy controls recruited by the Chengdu First People's Hospital. Grayscale ultrasound (US) of the rectus femoris was performed to measure thickness (RF_thick) and cross-sectional area (RF_csa). Shear wave elastography was used to determine the mean elasticity index (SWE_mean) of the rectus femoris (SWE_RFmean), vastus lateralis (SWE_VLmean) and vastus medialis (SWE_VMmean). Clinical features included dyspnea index score (modified British Medical Research Council (MMRC) score), COPD Assessment Test (CAT), the Five-Repetition Sit-to-Stand Test (5STS) and the Six-Minute Walk Test (6MWT). We compared the differences between US parameters and SWEmean in healthy controls and COPD patients. We also described the correlation between US parameters, SWE_mean and clinical features of patients with COPD.

Results

The intra-observer repeatability for the performance of using SWE to measure quadriceps stiffness was excellent (intraclass correlation coefficient (ICC)>0.75, p < 0.001). There was a statistically significant difference in the SWE_mean of the quadriceps (p < 0.001), but no significant difference in terms of RF_thic and RF_csa (p > 0.05) between healthy controls and COPD patients. The SWE_RFmean was positively correlated with the 6MWT (r = 0.959, p < 0.001), and negatively related to the mMRC (r=-0.825, p < 0.001), CAT (r=-0.993, p < 0.001) and 5STS (r=-0.936, p < 0.001). However, the RF_thic, RF_csa, SWE_VLmean and SWE_VMmean were not correlated with clinical features (p > 0.05).

Conclusion

As a supplement to US, SWE reflects changes of stiffness in the quadriceps of COPD patients, and can expanding the dimension of US for assessing the quadriceps. Furthermore, SWE_mean was associated with clinical features, and represents a potential index with which to reflect the clinical features of COPD patients.

Peripheral neuropathy: A neglected cause of disability in COPD - A narrative review

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory syndrome with systemic involvement leading to various cardiovascular, metabolic, and neurological comorbidities. It is well known that conditions associated with oxygen deprivation and metabolic disturbance are associated with polyneuropathy, but current data regarding the relationship between COPD and peripheral nervous system pathology is limited. This review summarizes the available data on the association between COPD and polyneuropathy, including possible pathophysiological mechanisms such as the role of hypoxia, proinflammatory state, and smoking in nerve damage; the role of cardiovascular and metabolic comorbidities, as well as the diagnostic methods and screening tools for identifying polyneuropathy. Furthermore, it outlines the available options for managing and preventing polyneuropathy in COPD patients. Overall, current data suggest that optimal screening strategies to diagnose polyneuropathy early should be implemented in COPD patients due to their relatively common association and the additional burden of polyneuropathy on quality of life.

Comprehensive multi-cohort transcriptional meta-analysis of muscle diseases identifies a signature of disease severity

Muscle diseases share common pathological features suggesting common underlying mechanisms. We hypothesized there is a common set of genes dysregulated across muscle diseases compared to healthy muscle and that these genes correlate with severity of muscle disease. We performed meta-analysis of transcriptional profiles of muscle biopsies from human muscle diseases and healthy controls. Studies obtained from public microarray repositories fulfilling quality criteria were divided into six categories: (i) immobility, (ii) inflammatory myopathies, (iii) intensive care unit (ICU) acquired weakness (ICUAW), (iv) congenital muscle diseases, (v) chronic systemic diseases, (vi) motor neuron disease. Patient cohorts were separated in discovery and validation cohorts retaining roughly equal proportions of samples for the disease categories. To remove bias towards a specific muscle disease category we repeated the meta-analysis five times by removing data sets corresponding to one muscle disease class at a time in a "leave-one-disease-out" analysis. We used 636 muscle tissue samples from 30 independent cohorts to identify a 52 gene signature (36 up-regulated and 16 down-regulated genes). We validated the discriminatory power of this signature in 657 muscle biopsies from 12 additional patient cohorts encompassing five categories of muscle diseases with an area under the receiver operating characteristic curve of 0.91, 83% sensitivity, and 85.3% specificity. The expression score of the gene signature inversely correlated with quadriceps muscle mass (r = -0.50, p-value = 0.011) in ICUAW and shoulder abduction strength (r = -0.77, p-value = 0.014) in amyotrophic lateral sclerosis (ALS). The signature also positively correlated with histologic assessment of muscle atrophy in ALS (r = 0.88, p-value = 1.62 × 10^-3) and fibrosis in muscular dystrophy (Jonckheere trend test p-value = 4.45 × 10^-9). Our results identify a conserved transcriptional signature associated with clinical and histologic muscle disease severity. Several genes in this conserved signature have not been previously associated with muscle disease severity.

Deaccelerated Myogenesis and Autophagy in Genetically Induced Pulmonary Emphysema

Patients with chronic obstructive pulmonary disease (COPD)-pulmonary emphysema often develop locomotor muscle dysfunction, which entails reduced muscle mass and force-generation capacity and is associated with worse outcomes, including higher mortality. Myogenesis contributes to adult muscle integrity during injury-repair cycles. Injurious events crucially occur in the skeletal muscles of patients with COPD in the setting of exacerbations and infections, which lead to acute decompensations for limited periods of time, after which patients typically fail to recover the baseline status they had before the acute event. Autophagy, which is dysregulated in muscles from patients with COPD, is a key regulator of muscle stem-satellite- cells activation and myogenesis, yet very little research has so far mechanistically investigated the role of autophagy dysregulation in COPD muscles. Using a genetically inducible interleukin-13-driven pulmonary emphysema model leading to muscle dysfunction, and confirmed with a second genetic animal model, we found a significant myogenic dysfunction associated with the reduced proliferative capacity of satellite cells. Transplantation experiments followed by lineage tracing suggest that an intrinsic defect in satellite cells, and not in the COPD environment, plays a dominant role in the observed myogenic dysfunction. RNA sequencing analysis and direct observation of COPD mice satellite cells suggest dysregulated autophagy. Moreover, while autophagy flux experiments with bafilomycin demonstrated deacceleration of autophagosome turnover in COPD mice satellite cells, spermidine-induced autophagy stimulation leads to a higher replication rate and myogenesis in these animals. Our data suggest that pulmonary emphysema causes disrupted myogenesis, which could be improved with stimulation of autophagy and satellite cells activation, leading to an attenuated muscle dysfunction.

Observation of the Effect of Singulair Combined With Ketotifen in the Treatment of Acute Exacerbation of Chronic Obstructive Pulmonary Disease With Airway Hyperresponsiveness and Its Influence on Th17/Treg

Objective

To investigate the effect of montelukast sodium (singulair) combined with ketotifen fumarate on the acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with airway hyperresponsiveness (AHR) and its effect on helper T cells 17 (Th17)/regulator T cells (Treg).

Methods

168 patients with AECOPD and AHR diagnosed in our hospital from February 2018 to December 2019 were selected, and divided into the observation group (n = 84) and the control group (n = 84). Both groups were given anti infection, bronchodilator, glucocorticoid, phosphodiesterase inhibitor, cough and expectorant. The observation group was additionally treated with singulair tablets and ketotifen tablets for 14 days. The curative effect were observed after treatment. The first second forced expiratory volume (FEV1), forced vital capacity (FVC) and FEV1 as percentage of predicted value (FEV1% pred), blood oxygen pressure (PaO₂) and blood carbon dioxide pressure (PaCO₂), high-sensitivity C-reactive protein (hs-CRP) and procalcitonin (PCT), Th17 and Treg levels were measured in both groups before and after treatment.

Results

Compared with the control group, the total effective rate after treatment in the observation group was increased (94.05 vs. 75.00%, P < 0.05). Compared with before treatment, the FEV1, FVC and FEV1%pred levels of the two groups of patients after treatment were increased (P < 0.05). Compared with the control group, the FEV1, FVC and FEV1%pred levels of the observation group were increased after treatment (P < 0.05). Compared with before treatment, the PaCO2, hs-CRP and PCT levels of the two groups of patients were reduced after treatment, and PaO2 levels were increased (P < 0.05). Compared with the control group, the PaCO2, hs-CRP and PCT levels in the observation group were reduced after treatment, and the PaO2 level was increased (P < 0.05). Compared with before treatment, Th17 and Th17/Treg levels of the two groups of patients were reduced after treatment, and Treg levels were increased (P < 0.05). Compared with the control group, the Th17 and Th17/Treg levels of the observation group were reduced after treatment, and the Treg levels was increased (P < 0.05).

Conclusion

Singulair combined with ketotifen in the treatment of patients with AECOPD combined with AHR can significantly improve the efficacy, improve lung function, reduce inflammatory response, and improve the balance of Th17/Treg, effectively controlling the disease.

Ultrasonic Elastography of the Rectus Femoris, a Potential Tool to Predict Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Purpose: Skeletal muscle dysfunction is common in patients with chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. Abnormal muscle quantity of the lower limbs is a manifestation of skeletal muscle dysfunction in patients with COPD. Shear wave ultrasound elastography (SWE) is a novel and possible tool to evaluate qualitative muscle parameters. This study explores the feasibility of SWE to measure the stiffness of the rectus femoris and evaluates its value in predicting sarcopenia in patients with COPD.

Methods: Ultrasound examination of the rectus femoris was performed to determine the mean elasticity index (SWE_mean), cross-sectional area (RF_csa), and thickness (RF_thick) using grayscale ultrasonography (US) and SWE in 53 patients with COPD and 23 age-matched non-COPD healthy controls. The serum levels of circulating biomarkers (GDF15, resistin, and TNF-α) were measured using ELISA. The definition of sarcopenia followed the guidelines from the Asian Working Group for Sarcopenia. Receiver operating characteristic (ROC) curve analysis of the SWE_mean, RF_thick, and RF_csa was used to evaluate their predictive ability for sarcopenia.

Results: The intraobserver and interobserver repeatability of SWE performance was excellent (all correlation coefficients > 0.95; p < 0.05). The SWE_mean of the rectus femoris in patients with COPD (8.98 ± 3.12 kPa) was decreased compared with that in healthy controls (17.00 ± 5.14 kPa) and decreased with advanced global initiative for chronic obstructive lung disease (GOLD) stage. Furthermore, SWE_mean was found to be independent of sex, height, and body mass, and a lower SWE_mean in patients with COPD was positively associated with reduced pulmonary function, worse physical function, poor exercise tolerance, decreased muscle strength, and worse dyspnea index score. The correlation between physical function [five-repetition sit-to-stand test (5STST)], muscle function, and SWE_mean was higher than those of RF_thick and RF_csa. In addition, SWE_mean was negatively correlated with serum GDF15 levels (r = −0.472, p < 0.001), serum resistin levels (r = −0.291, p = 0.035), and serum TNF-α levels (r = −0.433, p = 0.001). Finally, the predictive power of SWE_mean [area under the curve (AUC): 0.863] in the diagnosis of sarcopenia was higher than that of RF_thick (AUC: 0.802) and RF_csa (AUC: 0.816).

Conclusion: Compared with grayscale US, SWE was not affected by the patient’s height, weight, or BMI and better represented skeletal muscle function and physical function. Furthermore, SWE is a promising potential tool to predict sarcopenia in patients with COPD.

Body composition parameters and functional status test in predicting future acute exacerbation risk among hospitalized patients with chronic obstructive pulmonary disease

BACKGROUND & AIMS

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Nutritional and functional status derangement is a commonly seen in COPD patients, and this is associated with a higher disease severity and mortality. To assess body composition analysis - measured by segmental multi-frequency bioelectrical impedance analysis (BIA)- and functional status and investigate their relationship with the COPD acute exacerbation risk.

METHODS

Eighty COPD patients admitted to hospital for COPD acute exacerbation were prospectively followed-up for one year after discharge, focusing on a new incidence of COPD acute exacerbation. Following discharge, participants' body composition was assessed with the use of segmental multi-frequency BIA, whereas physical function by performing 5-repetitions and 30 s sit-to-stand (STS) tests. Unadjusted and multivariate logistic regression analyses were performed to evaluate the ability of the various measures to predict incidence of future COPD acute exacerbation in one-year period.

RESULTS

Seventy-six out of 80 participants completed the study and were analyzed. Fifty-one [24 male (47.1%)] out of 76 participants (67.1%), mean aged of 69.3 ± 8.9 years, developed at least one new COPD acute exacerbation during the one year follow-up. The probability of COPD acute exacerbation in one year was significantly related to BMI (OR = 0.75, 95% CI; 0.61-0.91, p = 0.004) and Fat Free Mass (OR = 0.88, 95% CI; 0.79-0.97, p = 0.012) after adjustment for sex, age and smoking index (pack × years). Both 5-repetitions and 30 s STS tests had a good predictive ability for the incidence of COPD acute exacerbation in one year (AUC = 0.80, 95% CI; 0.65-0.95, p = 0.009 and AUC = 0.83, 95% CI; 0.70-0.96, p = 0.004, respectively).

CONCLUSION

In an observational study among patients admitted with COPD acute exacerbation, body composition analysis parameters and functional status are related to acute exacerbation risk incidence.

Evaluation of the Level of Physical Activity and Muscle Strength of Quadriceps in Patients Hospitalized for E-COPD: A Longitudinal Study

Physical inactivity and peripheral muscle dysfunction are considered two of the main contributors to hospitalizations due to exacerbation and, above all, predictors of mortality for these requirements in patients with COPD. Therefore, longitudinal studies are needed to determine the impact of exacerbations during hospitalization on these two factors, especially after three months of hospital discharge. The objectives of the present study were to assess the level of physical activity in daily life (PADL) and isometric muscle strength of the quadriceps in patients hospitalized for exacerbation of COPD and to verify changes after 3 months of hospital discharge. This is a longitudinal observational study that assessed the PADL level with an accelerometer, after 24 h of the hospitalization and the beginning of the drug treatment and assessed the quadriceps muscle strength with a manual dynamometer, after 72 h of hospitalization, in 32 patients with COPD (66 ± 7.61 years), in addition to repeating both assessments with 30 days of hospital discharge and after 3 months of follow-up. Cognition, dyspnea, general health, physical performance and lung function were assessed to characterize the sample. As main results, there was increase in active time (344 ± 260 - 447 ± 199 min; p = 0.04) and number of steps (4.241 ± 374 - 6.216 ± 400 steps; p = 0.02) after three months. In addition, inactive time showed significant reduction 30 days after hospital discharge (1.151 ± 249 - 1.065 ± 198 min; p = 0.02). The level of physical activity showed significant improvement due to the increase in active time and number of steps after three months of hospital discharge and to the reduction of inactive time 30 days after hospital discharge.

Cushing Syndrome Associated Myopathy: It Is Time for a Change

Cushing syndrome is the result of excessive levels of glucocorticoids. Endogenous Cushing syndrome is rare with an incidence of two to three cases per million per year. Clinically, the presentation consists of a characteristic phenotype including skin symptoms and metabolic manifestations. A frequent co-morbidity with high impact on quality of life is Cushing syndrome associated myopathy. It characteristically affects the proximal myopathy, impairing stair climbing and straightening up. The pathophysiology is complex and involves protein degradation via the forkhead box O3 (FOXO3) pathway, intramuscular fat accumulation, and inactivity-associated muscle atrophy. Surgical remission of Cushing syndrome is the most important step for recovery of muscle function. Restoration depends on age, co-morbidities and postoperative insulin-like growth factor concentrations. At average, functionality remains impaired during the long-term compared to age and sex matched control persons. Growth hormone therapy in individuals with impaired growth hormone secretion could be an option but has not been proved in a randomized trial.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant

Extracorporeal membrane oxygenation (ECMO) is a cardiopulmonary technology capable of supporting cardiac and respiratory function in the presence of end-stage lung disease. Initial experiences using ECMO as a bridge to lung transplant (ECMO-BTLT) were characterized by high rates of ECMO-associated complications and poor posttransplant outcomes. More recently, ECMO-BTLT has garnered success in preserving patients' physiologic condition and candidacy prior to lung transplant due to technological advances and improved management. Despite recent growth, clinical practice surrounding use of ECMO-BTLT remains variable, with little data to inform optimal patient selection and management. Although many questions remain, the use of ECMO-BTLT has shown promising outcomes suggesting that ECMO-BTLT can be an effective strategy to ensure that complex and rapidly decompensating patients with end-stage lung disease can be safely transplanted with good outcomes. Further studies are needed to refine and inform practice patterns, management, and lung allocation in this high-risk and fragile patient population.

Association of exercise capacity and endothelial function in patients with severe exacerbations of chronic obstructive pulmonary disease

Severe acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with significant poor outcomes including an increased risk of cardiovascular (CV) events and exercise intolerance. Endothelial dysfunction might contribute to an impaired vascular homeostasis and consequently to CV events and exercise capacity. This study aimed to evaluate the association between exercise capacity and endothelial function in patients with severe AECOPD. Forty-five COPD patients diagnosed with severe AECOPD and admitted to the University Hospital of São Carlos from 2017 to 2019 were enrolled in this observational clinical study. Endothelial Function was assessed by brachial artery ultrasonography (M-Turbo, Sonosite, Bottle, WA, USA) and Flow Mediated Dilatation (FMD) technique in absolute (mm) and percentage values (%). Walking distance (6MWD) obtained by six-minute walk test was considered to characterize the exercise capacity. Pearson's correlation analysis and linear regression model were applied and a significance level of 5%. There was a significant positive correlation between exercise capacity and endothelial function. Pearson correlation coefficient were 0.36 (p = 0.02) and 0.40 (p = 0.01) between 6MWD and FMD in mm and %, respectively. Linear regression model revealed 6MWD (p = 0.007), accounting for 15% of FMD (%) variance (R2 adjusted). FMD (%) = 2.11 + (0.0081*6MWD). Exercise capacity is associated with endothelial function in patients with severe AECOPD. FMD was found to be increasing with increasing walked distance. Further research is needed to provide evidence of effectiveness of rehabilitation on exercise capacity and endothelial function in these patients and its prognostic value.

Towards Personalized Management of Sarcopenia in COPD

The awareness of the presence and consequences of sarcopenia has significantly increased over the past decade. Sarcopenia is defined as gradual loss of muscle mass and strength and ultimately loss of physical performance associated with aging and chronic disease. The prevalence of sarcopenia is higher in chronic obstructive pulmonary disease (COPD) compared to age-matched controls. Current literature suggests that next to physical inactivity, COPD-specific alterations in physiological processes contribute to accelerated development of sarcopenia. Sarcopenia in COPD can be assessed according to current guidelines, but during physical performance testing, ventilatory limitation should be considered. Treatment of muscle impairment can halt or even reverse sarcopenia, despite respiratory impairment. Exercise training and protein supplementation are currently at the basis of sarcopenia treatment. Furthermore, effective current and new interventions targeting the pulmonary system (eg, smoking cessation, bronchodilators and lung volume reduction surgery) may also facilitate muscle maintenance. Better understanding of disease-specific pathophysiological mechanisms involved in the accelerated development of sarcopenia in COPD will provide new leads to refine nutritional, exercise and physical activity interventions and develop pharmacological co-interventions.

Hypercapnic Respiratory Failure-Driven Skeletal Muscle Dysfunction: It Is Time for Animal Model-Based Mechanistic Research

Dysfunction of locomotor muscles is frequent in chronic pulmonary diseases and strongly associated with worse outcomes including higher mortality. Although these associations have been corroborated over the last decades, there is poor mechanistic understanding of the process, in part due to the lack of adequate animal models to investigate this process. Most of the mechanistic research has so far been accomplished using relevant individual stimuli such as low oxygen or high CO₂ delivered to otherwise healthy animals as surrogates of the phenomena occurring in the clinical setting. This review advocates for the development of a syndromic model in which skeletal muscle dysfunction is investigated as a comorbidity of a well-validated pulmonary disease model, which could potentially allow discovering meaningful mechanisms and pathways and lead to more substantial progress to treat this devastating condition.

Inflammation and Skeletal Muscle Wasting During Cachexia

Cachexia is the involuntary loss of muscle and adipose tissue that strongly affects mortality and treatment efficacy in patients with cancer or chronic inflammatory disease. Currently, no specific treatments or interventions are available for patients developing this disorder. Given the well-documented involvement of pro-inflammatory cytokines in muscle and fat metabolism in physiological responses and in the pathophysiology of chronic inflammatory disease and cancer, considerable interest has revolved around their role in mediating cachexia. This has been supported by association studies that report increased levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in some, but not all, cancers and in chronic inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and rheumatoid arthritis (RA). In addition, preclinical studies including animal disease models have provided a substantial body of evidence implicating a causal contribution of systemic inflammation to cachexia. The presence of inflammatory cytokines can affect skeletal muscle through several direct mechanisms, relying on activation of the corresponding receptor expressed by muscle, and resulting in inhibition of muscle protein synthesis (MPS), elevation of catabolic activity through the ubiquitin-proteasomal system (UPS) and autophagy, and impairment of myogenesis. Additionally, systemic inflammatory mediators indirectly contribute to muscle wasting through dysregulation of tissue and organ systems, including GCs via the hypothalamus-pituitary-adrenal (HPA) axis, the digestive system leading to anorexia-cachexia, and alterations in liver and adipocyte behavior, which subsequently impact on muscle. Finally, myokines secreted by skeletal muscle itself in response to inflammation have been implicated as autocrine and endocrine mediators of cachexia, as well as potential modulators of this debilitating condition. While inflammation has been shown to play a pivotal role in cachexia development, further understanding how these cytokines contribute to disease progression is required to reveal biomarkers or diagnostic tools to help identify at risk patients, or enable the design of targeted therapies to prevent or delay the progression of cachexia.

Role of acute exacerbations in skeletal muscle impairment in COPD

Introduction: Muscle impairments are prevalent in COPD and have adverse clinical implications in terms of physical performance capacity, disease burden, quality of life and even mortality. During acute exacerbations of COPD (AECOPDs) the respiratory symptoms worsen and this might also apply to the muscle impairments. Areas covered: This report includes a review of both clinical and pre-clinical peer-reviewed literature of the past 20 years found in PubMed providing a comprehensive view on the role of AECOPD in muscle dysfunction in COPD, the putative underlying mechanisms and the treatment perspectives. Expert opinion: The contribution of AECOPD and its recurrent nature to muscle impairment in COPD cannot be ignored and can be attributed to the acutely intensifying and converging disease-related drivers of muscle deterioration, in particular disuse, systemic inflammation and corticosteroid treatment. The search for novel treatment options should focus on the AECOPD-enhanced drivers of muscle dysfunction as well as on the underlying, mainly catabolic, mechanisms. Considering the impact of AECOPD on muscle function, and that of muscle impairment on the recurrence of exacerbations, counteracting muscle deterioration in AECOPD provides an unprecedented therapeutic opportunity.

Multimorbidity in Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a complex disease manifested primarily as airflow limitation that is partially reversible as confirmed by spirometry. COPD patients frequently develop systemic manifestations, such as skeletal muscle wasting and cachexia. COPD patients often develop other comorbid diseases, such as ischemic heart disease, heart failure, osteoporosis, anemia, lung cancer, and depression. Comorbidities complicate management of COPD and need to be evaluated because detection and treatment have important consequences. Novel approaches aimed at integrating the multiple morbidities seen in COPD and other chronic diseases will provide new avenues of research and allow developing more comprehensive and effective therapeutic approaches.

Six-minute stepper test in hospitalized elderly patients: Convergent validity, test-retest reliability and safety

OBJECTIVE

To evaluate the convergent validity of the six-minute stepper test (6MST) with the variables used in the diagnosis of sarcopenia (appendicular muscle mass, handgrip strength and six-meter gait speed test), as well as to evaluate test-retest reliability and safety when applied to hospitalized elderly patients. Finally, we aimed to compare the performance in the 6MST between hospitalized elderly patients and healthy elderly from the community.

MATERIALS AND METHODS

Observational and cross-sectional study. Elderly patients admitted to a private hospital and healthy elderly from the community were recruited. On the first day, the patients included underwent the following assessments: anthropometric, handgrip strength (HGS), six-meter gait speed test (6GST) and 6MST. On the second day, before breakfast, patients underwent body composition assessment. The healthy elderly were evaluated on a single day and performed only anthropometric assessment and 6MST.

RESULTS

30 hospitalized patients (age 71.0±7.9 years) and 15 healthy elderly (age 68.1±5.8 years) were included. There was a high correlation of 6MST with 6GST (r = 0.78; p<0.001), moderate correlation with HGS (r = 0.59; p<0.001) and low correlation with appendicular muscle mass (r = 0.45; p = 0.01). There was no statistical difference between the first and second 6MST performed by hospitalized elderly (196.2±91.0 cycles vs. 191.3±103.7 cycles; p = 0.66), in addition to an excellent agreement between these measures (ICC = 0.90; 95% IC 0.78-0.95). Only one adverse event (3.3%) occurred in the sample.

CONCLUSION

6MST showed convergent validity with the functional variables used in the diagnosis of sarcopenia. In addition, excellent test-retest reliability was observed, which indicates the need for a single assessment in hospitalized elderly patients. The prevalence of adverse events during the application of the test is low, without resulting in clinical symptoms; therefore, the test is considered safe for this population. In addition, hospitalized elderly patients perform worse in the 6MST compared to healthy elderly from the community.

Upper Limb Extremity Muscle-Dysfunction in Chronic Obstructive Pulmonary Disease: A Narrative Review

Background:

Peripheral muscle dysfunction is one of the major comorbidities seen in chronic obstructive pulmonary disease. Focusing more on upper extremity, unsupported elevation of arms results in a change in the recruitment pattern of the respiratory muscles. Over the years, many tests were developed to assess the upper limb capacity and include them in various rehabilitation protocol.

Objective:

To review the evidence on mechanism, tests, and rehabilitation protocol for the upper limb extremity muscle-dysfunction occurring in chronic obstructive pulmonary disease.

Methods:

PubMed and Google scholar databases were searched. Based on the inclusion criteria’s:- Chronic Obstructive Pulmonary Diseases patients, any Randomized Controlled or clinical trials, systematic reviews, explaining upper limb extremity muscle dysfunction, various tests to assess upper limb functional capacity and different ways of upper limb extremity training, a total of 15 articles were retrieved.

Results:

The mechanism of upper extremity muscle dysfunction is now well understood. Various tests were designed in order to assess arm strength, arm endurance and functional capacity. All the studies which included upper limb extremity training as a part of the rehabilitation program, showed beneficial results in terms of reduction of dyspnoea and arm fatigue, as well as improving the activity performing capacity.

Conclusion:

This review concluded that the alteration in the upper limb extremity muscles is an inevitable consequence of chronic obstructive pulmonary diseases, which can be confirmed by various upper extremity tests, with patients responding positively to the upper limb training incorporated during pulmonary rehabilitation protocols.