The systemic nature of chronic lung disease

Identification of genes and key pathways underlying the pathophysiological association between sarcopenia and chronic obstructive pulmonary disease

PURPOSE

Chronic obstructive pulmonary disease (COPD) patients are likely to develop sarcopenia, while the exact mechanism underlying the association between sarcopenia and COPD is still not clear. This cohort study aims to explore the genes, signaling pathways, and transcription factors (TFs) that are related to the molecular pathogenesis of sarcopenia and COPD.

METHODS

According to the strict inclusion criteria, two gene sets (GSE8479 for sarcopenia and GSE76925 for COPD) were obtained from the Gene Expression Omnibus (GEO) platform. Overlapping differentially expressed genes (DEGs) in sarcopenia and COPD were detected, and comprehensive bioinformatics analysis was conducted, including functional annotation, enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), construction of a protein-protein interaction (PPI) network, co-expression analysis, identification and validation of hub genes, and TFs prediction and verification.

RESULTS

In total, 118 downregulated and 92 upregulated common DEGs were detected. Functional analysis revealed that potential pathogenesis involves oxidoreductase activity and ferroptosis. Thirty hub genes were detected, and ATP metabolic process and oxidative phosphorylation were identified to be closely related to the hub genes. Validation analysis revealed that SAA1, C3, and ACSS2 were significantly upregulated, whereas ATF4, PPARGC1A, and MCTS1 were markedly downregulated in both sarcopenia and COPD. In addition, six TFs (NFKB1, RELA, IRF7, SP1, MYC, and JUN) were identified to regulate the expression of these genes, and SAA1 was found to be coregulated by NFKB1 and RELA.

CONCLUSION

This study uncovers potential common mechanisms of COPD complicated by sarcopenia. The hub gene SAA1 and the NF-κB signaling pathway could be involved, and oxidative phosphorylation and ferroptosis might be important contributors to this comorbidity.

The Relationship between Physical Activity, Depression and Anxiety in People with COPD: A Systematic Review and Meta-analyses

Depression and anxiety are related to physical activity among people with chronic obstructive pulmonary disease (COPD), although the strength and direction of the reported relationships are inconsistent. This study systematically synthesized the relationships between physical activity and i) depression and ii) anxiety in people with COPD. Physical activity measurement type (objective, self-report) was examined as a moderator of these relationships. A systematic search of physical activity and COPD was conducted from inception to February 2022 across 8 databases. Studies were included if they provided correlation coefficients for the relationship between measures of physical activity and depression or anxiety in people with COPD and were published in English. Two reviewers independently screened, reviewed and extracted data, with discrepancies resolved by a third reviewer. Across 13 studies, a small relationship was found between physical activity and depression, weighted r = -0.15, 95%CI [-0.21, -0.10], which was not moderated by physical activity measurement type. Across 8 studies, a negligible relationship was found between physical activity and anxiety, weighted r = -0.03, 95%CI [-0.11, 0.04], although this was moderated by physical activity measurement type, such that self-reported physical activity had a small negative relationship with anxiety (weighted r = -0.09, 95% CI [-0.15, -0.03]) and objectively measured physical activity had a small positive relationship (weighted r = 0.07, 95% CI [-0.13, 0.26]). In COPD, the bivariate association between physical activity and anxiety and depression are small.

Osteoporosis in Patients With Respiratory Diseases

Climate change, environmental pollution, and virus epidemics have sharply increased the number of patients suffering from respiratory diseases in recent years. Prolonged periods of illness and drug use increase the occurrence of complications in these patients. Osteoporosis is the common bone metabolism disease with respiratory disturbance, which affects prognosis and increases mortality of patients. The problem of osteoporosis in patients with respiratory diseases needs more attention. In this review, we concluded the characteristics of osteoporosis in some respiratory diseases including COPD, asthma, COVID-19, tuberculosis, and lung cancer. We revealed that hypoxia was the common pathogenesis of osteoporosis secondary to respiratory diseases, with malnutrition and corticosteroid abuse driving the progression of osteoporosis. Hypoxia-induced ROS accumulation and activated HIF-1α lead to attenuated osteogenesis and enhanced osteoclastogenesis in patients with respiratory diseases. Tuberculosis and cancer also invaded bone tissue and reduced bone strength by direct infiltration. For the treatment of osteoporosis in respiratory patients, oral-optimized bisphosphonates were the best treatment modality. Vitamin D was a necessary supplement, both for calcium absorption in osteogenesis and for improvement of respiratory lesions. Reasonable adjustment of the dose and course of corticosteroids according to the etiology and condition of patients is beneficial to prevent the occurrence and development of osteoporosis. Additionally, HIF-1α was a potential target for the treatment of osteoporosis in respiratory patients, which could be activated under hypoxia condition and involved in the process of bone remodeling.

Hand Grip Strength and Likelihood of Moderate-to-Severe Airflow Limitation in the General Population

Background and Objective

Sarcopenia is mainly results from aging; however, it is more prevalent in chronic airway disease such as obstructive pulmonary disease (COPD). Hand grip strength (HGS) can be used as an indicator to evaluate sarcopenia. We aimed to assess the association between HGS and severity of airflow limitation (AFL) in the general population.

Methods

We conducted a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2014 to 2018. Subjects aged ≥40 years who underwent both spirometry and HGS tests were included. AFL was defined by spirometry revealed forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) <0.70). A propensity score-matched comparison was performed, and the risk for moderate-to-very severe AFL was analyzed using logistic regression analysis.

Results

Among 15,950 subjects, 2277 (14.3%) had AFL with mean FEV₁ was 77.1% of the predicted value. Male was predominant in both individuals without AFL and with AFL (74.2% vs 73.5%, p = 0.613). The HGS was 32.9 ± 9.5 kg and 33.3 ± 9.5 kg in participants without AFL and with AFL (p = 0.109). However, HGS was significantly decreased as AFL getting more severe: 34.0 ± 9.6 kg in mild, 33.0 ± 9.5 kg in moderate, and 30.8 ± 8.5 kg in severe to very severe AFL group (p<0.001). As HGS decreased, adjusted odds for moderate-to-very severe AFL increased compared to those with mild AFL (adjusted odds ratio [aOR], 0.97; 95% confidence interval [CI], 0.951–0.987) and both without AFL and mild AFL group (aOR, 0.98; 95% CI, 0.967–0.995) in age-, sex-, and body mass index (BMI)-matched comparisons.

Conclusion

Lower HGS is significantly associated with moderate-to-very severe AFL in age-, sex-, and BMI-matched comparisons.

Self-efficacy and health-related quality of life in chronic obstructive pulmonary disease: A meta-analysis

OBJECTIVE

To determine the association between self-efficacy and health-related quality of life (HRQoL) in people with Chronic Obstructive Pulmonary Disease (COPD) and the moderating effect of self-efficacy type (exercise task, exercise barrier, COPD symptom, general) and HRQoL type (generic, COPD specific).

METHODS

Databases were searched systematically from inception to January 2019. Methodological quality was assessed, and a meta-analysis was conducted following PRISMA guidelines (PROSPERO protocol: CRD42018114846).

RESULTS

Across 31 coefficients, there was a positive relationship between self-efficacy and HRQoL (r = 0.38, 95 %CI [0.32, 0.45]). Exercise barrier self-efficacy had the strongest relationship to HRQoL (r = 0.42, 95 % CI [0.30, 0.52]), followed by COPD symptoms (r = 0.41, 95 % CI [0.33, 0.49]), exercise tasks (r = 0.40, 95 % CI [0.29, 0.50]), and general self-efficacy (r = 0.21, 95 % CI [0.14, 0.28]). Generic HRQoL had a similar relationship to self-efficacy (r = 0.38, 95 % CI [0.28, 0.47]) as COPD specific HRQoL (r = 0.38, 95 % CI [0.30, 0.46]).

CONCLUSION

There is a moderate positive relationship between self-efficacy and HRQoL in COPD, with the relationship stronger for exercise and COPD symptoms than general self-efficacy.

Coping Versus Mastery Modeling Intervention to Enhance Self-efficacy for Exercise in Patients with COPD

The literature suggests self-efficacy is a determinant of physical activity and management of Chronic Obstructive Pulmonary Disease (COPD). The purpose of this study was to (1) test the effects of two vicarious experience interventions, coping versus mastery modeling, on self-efficacy in COPD patients performing a cardiopulmonary exercise test (CPET), and (2) determine the type of self-efficacy most strongly related to physical activity in COPD patients. After a baseline assessment of self-efficacy (task, coping for exercise, coping for breathing, scheduling, and walking) and potential moderators, 120 COPD patients watched a mastery model or coping model CPET video, or received usual care verbal instructions. Then, self-efficacy was assessed, followed by a CPET, and another assessment of self-efficacy. Fitbits tracked participants' step count the week following contact. Repeated measures MANOVAs assessed the intervention effects and multiple regressions assessed the contribution of self-efficacy subtypes to step count. All self-efficacy subtypes improved in the mastery and coping conditions, although greater improvement of self-efficacy for coping with exercise barriers was observed in the coping condition. Self-efficacy did not improve in the control condition and no moderators were identified. Self-efficacy for coping with exercise barriers was the self-efficacy subtype most strongly related to step count. This research suggests modeling is a useful intervention technique to enhance self-efficacy in COPD patients, although coping models may be more beneficial than mastery models for enhancing capability beliefs during complex tasks. Future interventions in COPD patients should target self-efficacy for coping with exercise barriers.

Physiological response to the Glittre-ADL test in elderly COPD patients

Abstract Introduction: The Glittre-ADL (TGlittre) test was developed to assess functional capacity in a group of activities of daily living, but little is known about the physiological responses expected during its implementation. Objective: To evaluate the physiological responses induced by TGlittre in COPD patients and compare them with those induced by the 6-minute walk test (6MWT). Method: This is a cross-sectional study involving 15 elderly patients with COPD (70±6 years and predicted FEV1 of 47±16%). The TGlittre and 6MWT were performed on two different days, evaluating heart rate, peripheral oxygen saturation and perceived exertion in the 1st, 4th and 6th minutes of the 6MWT and at the start, after each lap and the end of TGlittre. After the normality test (Shapiro-Wilk), the Wilcoxon test was applied to compare the functional tests, and Spearman’s correlation coefficient to assess the association between variables. Results: At the end of TGlittre, heart rate was faster than in the 6MWT (106.7±21.9 vs 96.4±16.2bpm, p = 0.02). The other physiological variables were similar at the end of both tests. Heart rate at the end of TGlittre correlated with the final heart rate in the 6MWT (r = 0.69; p = 0.002). Conclusion: TGlittre induced a faster heart rate than in the 6MWT, with increased metabolic demand, but with similar ventilatory responses.

Sarcopenia in COPD: a systematic review and meta-analysis

COPD is associated with a progressive loss of muscle mass and function. However, there is an unmet need to define and standardise methods to estimate the prevalence of sarcopenia in COPD patients.

We performed a systematic review and meta-analysis of the prevalence of this extrapulmonary manifestation in COPD patients. We searched Embase, Medline (Ovid), CINAHL (EBSCO), Web of Science, Scopus and Google Scholar for studies published up to January 17, 2019, assessing sarcopenia in COPD patients based on low muscle mass and decreased muscle function. Interventional studies, in vitro experiments, protocols or reviews and meta-analyses were excluded. We estimated heterogeneity (I²) and assessed significance (Q) using a Chi-squared test for estimates obtained from random-effects models.

4465 articles were initially identified. After removing the duplicates and applying the selection criteria, we reviewed 62 full-text articles. Finally, 10 articles (n=2565 COPD patients) were included in this systematic review and meta-analyses. Overall, the prevalence of sarcopenia in patients with COPD was 21.6% (95% CI 14.6–30.9%, I²=94%), ranging from 8% in population-based to 21% in clinic-based studies, and 63% in COPD patients residing in nursing homes.

Sarcopenia is frequently observed in COPD patients, with varying prevalence across population settings. Sarcopenia in COPD should be assessed using standardised tests and cut-off points from sarcopenia consensus criteria for clinical practice and international comparisons.

We confirmed a high prevalence of sarcopenia in COPD patients, with varying prevalence across population settings. We recommend adhering to the sarcopenia consensus criteria to systematically evaluate the muscle health of COPD patients.http://bit.ly/2KA6weh

Short-term variations of optic coherence tomography findings in mild and severe chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the short-term changes in subfoveal choroidal thickness (SFCT), ganglion cell complex (GCC) analysis, and retinal nerve fiber length (RNFL) of patients with chronic obstructive pulmonary disease (COPD) in a 3-month follow-up.

MATERIALS AND METHODS

Forty-eight patients with COPD (96 eyes) and 40 control subjects (80 eyes) were enrolled in our study. COPD patients were grouped according to disease severity as Group 1 (mild-moderate) and Group 2 (advanced). GCC, RNFL, and SFCT analysis by Cirrus SD-OCT were obtained for all eyes, in two consecutive examinations with a 3-month interval.

RESULTS

SFCT in Group 2 was lower than Group 1 and control group in the initial and 3rd month examination (p < 0.001, respectively). Inferior RNFL in Group 2 were lower than control group in the initial and 3rd month examination (p = 0.002, p < 0.001, respectively) Temporal RNFL were lower in Group 2 than Group 1 in 3rd month examination (p = 0.009). Average, superior, superotemporal, inferior, and inferonasal GCC analyses of the Group 2 were lower than control group both in the initial and 3rd month examination (p = 0.001, p < 0.001, respectively) SFCT, average, and superior GCC of Group 2 were significantly reduced during the 3-month follow-up (p < 0.001).

CONCLUSION

Hypoxia is thought to be the underlying mechanism in COPD, which may influence retinal and choroidal OCT parameters. Decrease in blood flow of optic nerve head, increased vascular resistance, and reduced blood flow in choroid may affect the visual ability in these patients, which should be kept in mind during their follow-up.

Neuromuscular electrical stimulation improves muscle atrophy induced by chronic hypoxia-hypercapnia through the MicroRNA-486/PTEN/FoxO1 pathway

Previous work has confirmed that the chronic hypoxia-hypercapnia (CHH) associated with chronic obstructive pulmonary disease contributes to the development of skeletal muscle atrophy. Neuromuscular Electrical Stimulation (NMES) has shown some efficacy when used as a treatment to reduce skeletal muscle atrophy. The present study focuses on the MicroRNA-486/PTEN/FoxO1 pathway with the goal of identifying its physiological role in skeletal muscle atrophy induced by CHH as well as its role during NMES treatment. To test this, 32 male Sprague Dawley rats were randomly divided into four groups. After completion of the disease modeling, gastrocnemius muscles were collected from all animals and cross-sectional areas of muscular fiber were observed and analyzed via H&E staining. MiR-486 expression was further assessed by qRT-PCR, and protein levels of TNF-α, PTEN, p-Akt, Akt, FoxO1, atrogin-1 and MuRF1 were measured by immunohistochemistry and western blotting. CSA, miR-486, and the ratio p-Akt/Akt were significantly reduced in the CHH group, while the levels of TNF-α, PTEN, FoxO1, atrogin-1, and MuRF1 were markedly increased. Importantly, these findings were reversed as a result of NMES. Thus, the MicroRNA-486/PTEN/FoxO1 pathway functions in muscle protein synthesis and degradation. NEW & NOTEWORTHY: Our research provides a theoretical basis for the application of NMES as a means of improving muscle atrophy. Moreover, these therapeutic targets provide possible clues relevant to the treatment of amyotrophic diseases.

Choroid and Retinal Nerve Fiber Layer Thickness in Patients with Chronic Obstructive Pulmonary Disease Exacerbation

PURPOSE

We aimed at measuring the choroid and retinal nerve fiber layer thickness with optic coherence tomography (OCT) in patients diagnosed with chronic obstructive pulmonary disease (COPD).

METHODS

A total of 60 patients with COPD and 23 healthy controls were evaluated in the scope of this prospective, observational study. COPD patients were divided into two groups as those that were stable and those with an exacerbation based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. Subfoveal choroid thickness (SFCT) of the patients and the control group was compared by measuring the choroid thickness at points 1000 µm nasal and temporal to the fovea and the mean retinal nerve fiber layer (RNFL) thickness.

RESULTS

The subfoveal choroid thickness of the COPD patients in both the exacerbation and stable groups was found to be statistically significantly thinner than the control group (p=0.047 and p=0.046, resp.). No statistically significant difference was found between the subfoveal choroid thickness of the patients that were stable and those that had an exacerbation (p=0.813). No statistically significant difference was found between the mean RNFL, 1000 µm nasal, or 1000 µm temporal choroid thicknesses of the COPD patients and the control group (p=0.263, p=0.455, and p=0.611, resp.).

CONCLUSION

Decreased subfoveal choroid thickness was found in the COPD patients both during an exacerbation and in the stable period, when compared to the control group. The mean RNFL thickness was similar in the exacerbation and stable period of the stable COPD patients when compared to the control group. This suggests that ocular findings might be important in terms of COPD morbidity. This trial is registered with www.chictr.org.cn/enIndex.aspx.

Pilates in noncommunicable diseases: A systematic review of its effects

OBJECTIVES

Chronic cardiovascular diseases, cancer, chronic respiratory diseases and diabetes are the four major groups of non-communicable diseases (NCDs) and the main cause of mortality worldwide. Pilates has been described as an effective intervention to promote healthy behaviors and physical activity in people with chronic diseases. However, the evidence of its effects in NCDs have not been systematized. We investigated the effects of Pilates in the four major groups of NCDs.

DESIGN

A systematic review was performed. Searches were conducted on Cochrane Library, EBSCO, PubMed, Science Direct, Scopus and Web of Science databases. Studies were rated with the quality assessment tool for quantitative studies. As a meta-analysis was not possible to conduct, a best-evidence synthesis was used.

RESULTS

Twelve studies, mostly of moderate quality, were included with 491 participants (78.6% females; age range 13-70 years old) with breast cancer (n = 3), diabetes (n = 3), chronic stroke (2 years post stroke) (n = 2), chronic obstructive pulmonary disease (n = 1), cystic fibrosis (n = 1), heart failure (n = 1) and arterial hypertension (n = 1). The best-evidence synthesis revealed strong evidence for improving exercise tolerance; moderate evidence for improving symptoms, muscle strength and health-related quality of life and limited or conflicting evidence on vital signs, metabolic parameters, body composition, respiratory function, functional status, balance, flexibility and social support.

CONCLUSIONS

Pilates should be considered for patients with NCDs, as it improves exercise tolerance. Future studies with robust methodologies are still needed to clarify its effectiveness on outcomes with moderate, limited or conflicting evidence and to establish the most suitable intervention protocol.

Risk of Sarcopenia and Osteoporosis in Male Tuberculosis Survivors: Korea National Health and Nutrition Examination Survey

Short-term prospective studies have suggested that pulmonary tuberculosis (TB) preludes permanent loss of lean tissue and fat mass even when TB treatment is effective. The aim of this study was to estimate the risk of sarcopenia and osteoporosis among Korean male TB survivors. Data of the population-based, Korea National Health and Nutrition Examination Survey (KNHANES) (2008–2011) were analyzed, including 3,228 males aged 50 years or older who underwent chest X-ray (CXR) and dual-energy x-ray absorptiometry (DEXA). TB survivors having both medical history and TB scars on CXR had increased risk of sarcopenia (odds ratio [OR] 3.44, 95% confidence interval [CI] 1.79–6.68) and osteoporosis (OR 1.75, 95% CI 1.04–2.95) after adjusting for age, height, smoking, alcohol, physical activity, serum 25-hydroxyvitamin D, parathyroid hormone level, education, and fat mass index. Having TB scars on CXR without medical history of TB was an independent risk factor of sarcopenia (OR 2.05, 95% CI 1.05–4.00), but not a risk factor of osteoporosis. Sarcopenia and low bone mineral density are prevalent in pulmonary TB survivors with TB scars on CXR. Medical history of TB with TB scars on CXR is an independent risk factor for sarcopenia and osteoporosis.

Subclinical carotid atherosclerosis in patients with chronic obstructive pulmonary disease: a meta-analysis of literature studies

BACKGROUND

Chronic obstructive pulmonary disease (COPD) patients have an increased cardiovascular (CV) morbidity and mortality. Common carotid intima-media thickness (CCA-IMT) and carotid plaques are surrogate markers of subclinical atherosclerosis and predictors of CV events.

METHODS AND RESULTS

We performed a meta-analysis to evaluate the association between COPD and subclinical atherosclerosis. Studies evaluating the impact of COPD on CCA-IMT and on the prevalence of carotid plaques were systematically searched.

RESULTS

Twenty studies (2082 COPD patients and 4844 controls) were included, 12 studies with data on CCA-IMT (13 data-sets on 1180 COPD patients and 2312 controls) and 12 studies reporting on the prevalence of carotid plaques (1231 COPD patients and 4222 controls). Compared to controls, COPD patients showed a significantly higher CCA-IMT (mean difference [MD]: 0.201 mm; 95%CI: 0.142, 0.260; p < .001), and an increased prevalence of carotid plaques (Odds Ratio [OR]: 2.503; 95%CI: 1.333, 2.175; p < .0001). Meta-regression models showed a direct association between disease severity [as expressed by Global Initiative for Chronic Obstructive Lung Disease (GOLD) class] and the difference in the risk of carotid plaques presence between COPD patients and controls.

CONCLUSIONS

COPD is significantly associated with subclinical atherosclerosis. These findings may be useful to plan adequate CV prevention strategies. Key messages COPD patients show a higher CCA-IMT and an increased prevalence of carotid plaques compared with controls. A more severe pulmonary disease is associated with a higher prevalence of carotid plaques in COPD patients. Screening for subclinical atherosclerosis may be worthy in COPD patients to plan specific prevention strategies.

New aspect for systemic effects of COPD: eye findings

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) has multisystemic implications and comorbidities. Hypoxia and systemic inflammation are thought to involve oculary structures. In this study, our aim is to evaluate retinal nerve fiber and choroidal thickness and retinal vessel diameter using the spectral-domain optical coherence tomography (SD-OCT) in COPD subjects.

METHODS

Forty-three subjects diagnosed with COPD according to the Global Initiative for Chronic Obstructive Lung Disease criteria at the Pulmonology Department of Pamukkale University were enrolled in the study. All subjects underwent respiratory function testing and a carbon monoxide diffusion test. To determine hypoxic state, arterial blood gas analysis was performed. The control group consisted of 31 subjects with comparable age and gender distribution. All participants underwent a standard ophthalmic examination including visual acuity assessment, biomicroscopy, air-puff tonometry, indirect retinoscopy, and SD-OCT measurements.

RESULTS

The mean subfoveal choroidal thickness (SFCT), foveal thickness, and retinal arteriolar caliber were found to be similar in both groups, while the mean retinal venular caliber value was markedly higher in the COPD group. The mean peripapillary retinal nerve fiber layer (RNFL) thickness was 100.2±11.8 µm in the COPD group and 105.6 ± 8.1 µm in the control group (P = .03). The inferior quadrant RNFL was significantly thinner in the COPD group.

CONCLUSIONS

The results of this study showed increasing diameter of the retinal veins, thinning of the RNFL, and SFCT may be associated to chronic inflammation and hypoxia in subjects with COPD. Future guidelines may include ocular findings to the present systemic manifestations of COPD.

Sex differences in reported and objectively measured sleep in COPD

Background

The aim was to assess and compare reported sleep disturbances and objectively measured sleep in men and women with COPD compared with controls and also explore sex differences.

Methods

A total of 96 patients with COPD and 90 age- and sex-matched controls answered a sleep questionnaire, underwent ambulatory polysomnography, a post-bronchodilatory spirometry, and blood sampling.

Results

Of the patients with COPD, 51% reported sleep disturbances as compared with 31% in controls (P=0.008). Sleep disturbances were significantly more prevalent in males with COPD compared with controls, whereas there was no significant difference in females. The use of hypnotics was more common among patients with COPD compared with controls, both in men (15% vs 0%, P=0.009) and women (36% vs 16%, P=0.03). The men with COPD had significantly longer recorded sleep latency than the male control group (23 vs 9.3 minutes, P<0.001), while no corresponding difference was found in women. In men with COPD, those with reported sleep disturbances had lower forced vital capacity, higher C-reactive protein, myeloperoxidase, and higher prevalence of chronic bronchitis.

Conclusion

The COPD was associated with impaired sleep in men while the association was less clear in women. This was also confirmed by recorded longer sleep latency in male subjects with COPD compared with controls.

β₂ adrenergic receptor activation suppresses bone morphogenetic protein (BMP)-induced alkaline phosphatase expression in osteoblast-like MC3T3E1 cells

β adrenergic stimulation suppresses bone formation in vivo while its actions in osteoblastic differentiation are still incompletely understood. We therefore examined the effects of β2 adrenergic stimulation on osteoblast-like MC3T3-E1 cells focusing on BMP-induced alkaline phosphatase expression. Morphologically, isoproterenol treatment suppresses BMP-induced increase in the numbers of alkaline phosphatase-positive small foci in the cultures of MC3T3-E1 cells. Biochemically, isoproterenol treatment suppresses BMP-induced enzymatic activity of alkaline phosphatase in a dose-dependent manner. Isoproterenol suppression of alkaline phosphatase activity is observed even when the cells are treated with high concentrations of BMP. With respect to cell density, isoproterenol treatment tends to suppress BMP-induced increase in alkaline phosphatase expression more in osteoblasts cultured at higher cell density. In terms of treatment protocol, continuous isoproterenol treatment is compared to cyclic treatment. Continuous isoproterenol treatment is more suppressive against BMP-induced increase in alkaline phosphatase expression than cyclic regimen. At molecular level, isoproterenol treatment suppresses BMP-induced enhancement of alkaline phosphatase mRNA expression. Regarding the mode of isoproterenol action, isoproterenol suppresses BMP-induced BRE-luciferase activity. These data indicate that isoproterenol regulates BMP-induced alkaline phosphatase expression in osteoblast-like MC3T3E1 cells.

Osteoporotic Vertebral Fractures as Part of Systemic Disease

Our understanding of the genetic control of skeletogenesis and bone remodeling is expanding, and normally, bone resorption and bone formation are well balanced through regulation by hormones, growth factors, and cytokines. Osteoporosis is considered a systemic disease characterized by low bone mass and microarchitectural deterioration of bone tissue. Consequent increased bone fragility results in higher fracture risk. The most common osteoporotic fractures are located in the spine, and they form a significant health issue. A large variety of systemic diseases are associated with risk of osteoporotic vertebral fractures, illustrating its multifactorial etiology. Prevalences of these conditions vary from common to extremely rare, and incidence peaks differ according to etiology. This review appreciates different aspects of osteoporotic vertebral fractures as part of systemic disease, including genetic, immunologic, inflammatory, metabolic, and endocrine pathways. It seems impossible to be all-comprehensive on this topic; nevertheless, we hope to provide a reasonably thorough overview. Plenty remains to be elucidated in this field, identifying even more associated diseases and further exposing pathophysiological mechanisms underlying osteoporotic vertebral fractures.

Muscle dysfunction in chronic obstructive pulmonary disease: update on causes and biological findings

Respiratory and/or limb muscle dysfunction, which are frequently observed in chronic obstructive pulmonary disease (COPD) patients, contribute to their disease prognosis irrespective of the lung function. Muscle dysfunction is caused by the interaction of local and systemic factors. The key deleterious etiologic factors are pulmonary hyperinflation for the respiratory muscles and deconditioning secondary to reduced physical activity for limb muscles. Nonetheless, cigarette smoke, systemic inflammation, nutritional abnormalities, exercise, exacerbations, anabolic insufficiency, drugs and comorbidities also seem to play a relevant role. All these factors modify the phenotype of the muscles, through the induction of several biological phenomena in patients with COPD. While respiratory muscles improve their aerobic phenotype (percentage of oxidative fibers, capillarization, mitochondrial density, enzyme activity in the aerobic pathways, etc.), limb muscles exhibit the opposite phenotype. In addition, both muscle groups show oxidative stress, signs of damage and epigenetic changes. However, fiber atrophy, increased number of inflammatory cells, altered regenerative capacity; signs of apoptosis and autophagy, and an imbalance between protein synthesis and breakdown are rather characteristic features of the limb muscles, mostly in patients with reduced body weight. Despite that significant progress has been achieved in the last decades, full elucidation of the specific roles of the target biological mechanisms involved in COPD muscle dysfunction is still required. Such an achievement will be crucial to adequately tackle with this relevant clinical problem of COPD patients in the near-future.

Hypoxic regulation of osteoclast differentiation and bone resorption activity

Bone integrity is maintained throughout life via the homeostatic actions of bone cells, namely, osteoclasts, which resorb bone, and osteoblasts, which produce bone. Disruption of this balance in favor of osteoclast activation results in pathological bone loss, which occurs in conditions including osteoporosis, rheumatoid arthritis, primary bone cancer, and cancer metastasis to bone. Hypoxia also plays a major role in these conditions, where it is associated with disease progression and poor prognosis. In recent years, considerable interest has arisen in the mechanisms whereby hypoxia and the hypoxia-inducible transcription factors, HIF-1α and HIF-2α, affect bone remodeling and bone pathologies. This review summarizes the current evidence for hypoxia-mediated regulation of osteoclast differentiation and bone resorption activity. Role(s) of HIF and HIF target genes in the formation of multinucleated osteoclasts from cells of the monocyte-macrophage lineage and in the activation of bone resorption by mature osteoclasts will be discussed. Specific attention will be paid to hypoxic metabolism and generation of ATP by osteoclasts. Hypoxia-driven increases in both glycolytic flux and mitochondrial metabolic activity, along with consequent generation of mitochondrial reactive oxygen species, have been found to be essential for osteoclast formation and resorption activity. Finally, evidence for the use of HIF inhibitors as potential therapeutic agents targeting bone resorption in osteolytic disease will be discussed.

Airway and lung remodelling in chronic pulmonary obstructive disease: a role for muscarinic receptor antagonists?

Lung tissue remodelling in chronic inflammatory lung diseases has long been regarded as a follow-up event to inflammation. Recent studies have indicated that, although airway and lung tissue remodelling is often independent of inflammation, it precedes or causes inflammation. None of the available therapies has a significant effect on airway and lung tissue remodelling in asthma, bronchiectasis, fibrosis and chronic obstructive pulmonary disease (COPD). The goal of stopping or reversing lung tissue remodelling is difficult, as the term summarizes the net effect of independent events, including (1) cell proliferation, (2) cell volume increase, (3) cell migration, (4) modified deposition and metabolism of specific extracellular matrix components, and (5) local action of infiltrated inflammatory cells. The extracellular matrix of the lung has a very high turnover, and thus small changes may accumulate to significant structural pathologies, which seem to be irreversible. The most important question is 'why are pathological changes of the lung structure irreversible and resistant to drugs?' Many drugs have the potential to reduce remodelling mechanisms in vitro but fail in clinical trials. New evidence suggests that muscarinic receptor inhibitors have the potential to improve lung function through modifying tissue remodelling. However, the role of muscarinic receptors in lung remodelling, especially their supportive role for other remodelling driving factors, needs to be further investigated. The focus of this review is the role of muscarinic receptors in lung tissue remodelling as it has been reported in the human lung.

Long-term effects of acupuncture treatment on airway smooth muscle in a rat model of smoke-induced chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is one of the most common lung diseases. It is a chronic inflammatory process characterised by airway obstruction and progressive lung inflammation, associated with difficulty breathing and insensitivity to corticosteroid therapy. Although there is some preliminary evidence to suggest a beneficial effect of acupuncture on COPD, its mechanism of action has not been investigated. Our aim was to examine the anti-inflammatory effects of acupuncture in a rat model of COPD induced by exposure to cigarette smoke (CS).

Methods

Sixty Sprague–Dawley rats were exposed to the smoke of 15 cigarettes for 1 h/day, 6 days/week for 3 months to induce COPD and treated with acupuncture at BL13 (Feishu), BL23 (Shenshu) and Dingchuan (COPD+Acupuncture, n=15), sham acupuncture (COPD+Sham, n=15) or left untreated (n=15). Exposed rats were compared with controls not exposed to CS (control, n=15). Pulmonary function was measured, and tumour necrosis factor-α (TNF-α) and interleukin-8 (IL-8) levels were determined in bronchoalveolar lavage fluid by ELISA. Histone deacetylase 2 (HDAC2) protein and mRNA expression were examined in lung tissue and in bronchus.

Results

Acupuncture treatment appeared to protect pulmonary function and reduce the COPD-induced inflammatory response by decreasing cell inflammation and the production of TNF-α and IL-8. Acupuncture also enhanced HDAC2 mRNA and protein expression, suggesting a possible direct effect on protein structure through post-translational modifications.

Conclusions

Our results suggest that acupuncture regulates inflammatory cytokines and contributes to lung protection in a rat model of smoke-induced COPD by modulating HDAC2.