Chronic obstructive pulmonary disease and exacerbations: clinician insights from the global Hidden Depths of COPD survey

Human rhinovirus infection and COPD: role in exacerbations and potential for therapeutic targets

INTRODUCTION

Respiratory virus infections (predominantly rhinoviruses) are the commonly identified in COPD exacerbations but debate about their role as a trigger of exacerbations continues. Experimental infection studies have provided significant new evidence establishing a causal relationship between virus infection and COPD exacerbations and contributed to a better understanding of the mechanisms of virus-induced exacerbations. However as yet no anti-viral treatments have undergone clinical trials in COPD patients.

AREAS COVERED

This review discusses the evidence for and against respiratory viruses being the main trigger of COPD exacerbations from both epidemiological studies and experimental infection studies. The host immune response to rhinovirus infection and how abnormalities in host immunity may underlie increased susceptibility to virus infection in COPD are discussed and the role of dual viral-bacterial infection in COPD exacerbations. Finally the current state of anti-viral therapy is discussed and how these may be used in the future treatment of COPD exacerbations.

EXPERT OPINION

Respiratory virus infections are the trigger of a substantial proportion of COPD exacerbations and rhinoviruses are the most common virus type. Clinical trials of anti-viral agents are needed in COPD patients to determine whether they are effective in virus-induced COPD exacerbations.

Alantolactone suppresses inflammation, apoptosis and oxidative stress in cigarette smoke-induced human bronchial epithelial cells through activation of Nrf2/HO-1 and inhibition of the NF-κB pathways

BACKGROUND

It is well established that airway remodeling and inflammation are characteristics for chronic obstructive pulmonary disease (COPD). Moreover, cigarette smoke extract (CSE) promots inflammation, apoptosis and oxidative stress in COPD. And, there is evidence suggested that alantolactone (ALT), a sesquiterpene lactone isolated from Inula helenium, plays an adverse role in inflammation, apoptosis and oxidative stress. However, few studies have investigated the function and mechanism of ALT treatment on the COPD pathological process.

METHODS

The levels of IL-1 β, TNF-α, IL-6 and IFN-γ were examined by ELISA. Cells' apoptosis and caspase-3 activity were detected by Cell Death Detection PLUS enzyme-linked immunosorbent assay and caspase-Glo 3/7 Assay, respectively. The content of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by using MDA and SOD assay kits. Reactive oxygen species (ROS) generation was measured by DCFH-DA assay. Protein expression was assayed by Western blot.

RESULTS

In the present study, we aimed to observe the protective effects of ALT against inflammation, apoptosis and oxidative stress in human bronchial epithelial Beas-2B and NHBE cells. Our results showed that different doses of CSE exposure induced Beas-2B and NHBE cell inflammatory cytokines IL-1 β, TNF-α, IL-6 and IFN-γ expression, cell apoptosis, caspase-3 activity and mediated oxidative stress markers MDA, ROS and SOD levels, while ALT treatment counteracted the effects of CSE. Further studies suggested that ALT attenuated NF-κB pathway activation. ALT also activated the Nrf2/HO-1 signal pathway through promoting Nrf2 nuclear aggregation and downstream HO-1 protein expression. HO-1 inhibitor tin protoporphyrin IX (SnPP IX) reversed the effects of ALT on Beas-2B and NHBE cell inflammation, apoptosis and oxidative stress.

CONCLUSIONS

The above results collectively suggested that ALT suppressed CSE-induced inflammation, apoptosis and oxidative stress by modulating the NF-ĸB and Nrf2/ HO-1 axis.

Ginsenoside Rb3 exerts protective properties against cigarette smoke extract-induced cell injury by inhibiting the p38 MAPK/NF-κB and TGF-β1/VEGF pathways in fibroblasts and epithelial cells

Cigarette smoke causes many adverse effects such as inflammation, oxidative stress, and excessive accumulation of the extracellular matrix (ECM). Ginsenoside Rb3 has anti-inflammatory and anti-oxidative effects, which may contribute to delaying the injury caused by cigarette smoke. In this study, we used cigarette smoke extract (CSE) to establish cell injury models in WI-38 human fetal lung fibroblasts and 16HBE human bronchial epithelial cells. Our results showed that Rb3 protected against CSE-induced cytotoxicity in both cell lines. In addition, it significantly inhibited the secretion of inflammatory factors, such as interleukin-8 and tumor necrosis factor alpha, by inhibiting the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB). Moreover, Rb3 pre-treatment led to an increase in the levels of glutathione (GSH) and activities of superoxide dismutase, glutathione peroxidase (GSH-Px), and catalase to reduce the oxidative stress induced by CSE. Additionally, Rb3 decreased the levels of ECM proteins including collagen I (Col I), Col III, and elastin after CSE treatment by inhibiting the expression of transforming growth factor beta 1 (TGF-β1)-induced vascular endothelial growth factor (VEGF). Our findings suggest that Rb3 prevented CSE-induced inflammation and oxidative stress as well as the excessive accumulation of ECM in WI-38 and 16HBE cells to protect against cell injury by inhibiting the p38 MAPK/NF-κB and TGF-β1/VEGF pathways. The results of this study may be valuable for the development of Rb3 to combat the damage caused by cigarette smoke.

Quercetogetin protects against cigarette smoke extract-induced apoptosis in epithelial cells by inhibiting mitophagy

Recent studies demonstrate that the autophagy-dependent turnover of mitochondria (mitophagy) mediates pulmonary epithelial cell death in response to cigarette smoke extract (CSE) exposure, and contributes to emphysema development in vivo during chronic cigarette smoke (CS)-exposure, although the underlying mechanisms remain unclear. Here, we investigated the role of mitophagy in regulating apoptosis in CSE-exposed human lung bronchial epithelial cells. Furthermore, we investigated the potential of the polymethoxylated flavone antioxidant quercetogetin (QUE) to inhibit CSE-induced mitophagy-dependent apoptosis. Our results demonstrate that CSE induces mitophagy in epithelial cells via mitochondrial dysfunction, and causes increased expression levels of the mitophagy-regulator protein PTEN-induced putative kinase-1 (PINK1) and the mitochondrial fission protein dynamin-1-like protein (DRP-1). CSE induced epithelial cell death and increased the expression of the apoptosis-related proteins cleaved caspase-3, -8 and -9. Caspase-3 activity was significantly increased in Beas-2B cells exposed to CSE, and decreased by siRNA-dependent knockdown of DRP-1. Treatment of epithelial cells with QUE inhibited CSE-induced mitochondrial dysfunction and mitophagy by inhibiting phospho (p)-DRP-1 and PINK1 expression. QUE suppressed mitophagy-dependent apoptosis by inhibiting the expression of cleaved caspase-3, -8 and -9 and downregulating caspase activity in human bronchial epithelial cells. These findings suggest that QUE may serve as a potential therapeutic in CS-induced pulmonary diseases.

The Phosphodiesterase 4 Inhibitor Roflumilast Protects against Cigarette Smoke Extract-Induced Mitophagy-Dependent Cell Death in Epithelial Cells

Background

Recent studies show that mitophagy, the autophagy-dependent turnover of mitochondria, mediates pulmonary epithelial cell death in response to cigarette smoke extract (CSE) exposure and contributes to the development of emphysema in vivo during chronic cigarette smoke (CS) exposure, although the underlying mechanisms remain unclear.

Methods

In this study, we investigated the role of mitophagy in the regulation of CSE-exposed lung bronchial epithelial cell (Beas-2B) death. We also investigated the role of a phosphodiesterase 4 inhibitor, roflumilast, in CSE-induced mitophagy-dependent cell death.

Results

Our results demonstrated that CSE induces mitophagy in Beas-2B cells through mitochondrial dysfunction and increased the expression levels of the mitophagy regulator protein, PTEN-induced putative kinase-1 (PINK1), and the mitochondrial fission protein, dynamin-1-like protein (DRP1). CSE-induced epithelial cell death was significantly increased in Beas-2B cells exposed to CSE but was decreased by small interfering RNA-dependent knockdown of DRP1. Treatment with roflumilast in Beas-2B cells inhibited CSE-induced mitochondrial dysfunction and mitophagy by inhibiting the expression of phospho-DRP1 and -PINK1. Roflumilast protected against cell death and increased cell viability, as determined by the lactate dehydrogenase release test and the MTT assay, respectively, in Beas-2B cells exposed to CSE.

Conclusion

These findings suggest that roflumilast plays a protective role in CS-induced mitophagy-dependent cell death.

Characterisation of the frequent exacerbator phenotype in COPD patients in a large UK primary care population

BACKGROUND

The 'frequent exacerbator' is recognised as an important phenotype in COPD. Current understanding about this phenotype comes from prospective longitudinal clinical trials in secondary/tertiary care with little information reported in primary care populations.

AIMS

To characterize the frequent-exacerbator phenotype and identify associated risk factors in a large UK primary care COPD population.

METHODS

Using a large database of primary care patients from 80 UK general practices, patients were categorised using GOLD 2014 criteria into high and low risk groups based on exacerbation history. A multivariate logistic regression model was used to investigate covariates associated with the frequent-exacerbator phenotype and risk of experiencing a severe exacerbation (leading to hospitalisation).

RESULTS

Of the total study population (n = 9219), 2612 (28%) fulfilled the criteria for high risk frequent-exacerbators. Independent risk factors (adjusted odds ratio [95% CI]) for ≥2 exacerbations were: most severely impaired modified Medical Research Council (mMRC) dyspnoea score (mMRC grade 4: 4.37 [2.64-7.23]), lower FEV1 percent predicted (FEV1 <30%: 2.42 [1.61-3.65]), co-morbid cardiovascular disease (1.42 [1.19-1.68]), depression (1.56 [1.22-1.99]) or osteoporosis (1.54 [1.19-2.01]), and female gender (1.20 [1.01-1.43]). Older patients (≥75 years), those with most severe lung impairment (FEV1 <30%), those with highest mMRC score and those with co-morbid osteoporosis were identified as most at risk of experiencing exacerbations requiring hospitalisation.

CONCLUSIONS

Although COPD exacerbations occur across all grades of disease severity, female patients with high dyspnoea scores, more severely impaired lung function and co-morbidities are at greatest risk. Elderly patients, with severely impaired lung function, high mMRC scores and osteoporosis are associated with experience of severe exacerbations requiring hospitalisation.

Experimentation with aerosol bonsetan, pirfenidone, treprostinil and sidenafil

INTRODUCTION

Pulmonary hypertension (PH) has been identified either as a symptom or a primary entity. Several drugs are already on the market and other are being investigated. Idiopathic pulmonary fibrosis (IPF) is also a disease were several drugs are being investigated.

MATERIALS AND METHODS

Three jet nebulizers and three ultrasound nebulizers were used for our experiments with seven different residual cups and four different loadings. Bonsetan, treprostinil, sidenafil and pirfenidone were modified in order to be produced as aerosol in an effort to identify parameters which influence the droplet size production size.

RESULTS

The four-way ANOVA on droplet size using the jet nebulizers revealed two statistically significant factors, drug (F=6.326, P=0.0007) and residual cup (F=4.419, P=0.0007), and their interaction term (F=5.829, P<0.0001). Drugs bonsetan and pirfenidone produce equally the lowest mean droplet size (2.63 and 2.80 respectively) as compared to other two drug mean sizes. The ANOVA results, concerning the ultrasound nebulizers, revealed only the nebulizers as producing significant effect on droplet size (F=4.753, P=0.037).

DISCUSSION

Our study indicates the importance of the initial drug design formulation. Moreover, further investigation of the residual cup design is an additional parameter that can assist in the optimal droplet size production, indifferently of the drug formulation.

Symptoms and impact of symptoms on function and health in patients with chronic obstructive pulmonary disease and chronic heart failure in primary health care

Background

Patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) seem to have several symptoms in common that impact health. However, methodological differences make this difficult to compare.

Aim

Comparisons of symptoms, impact of symptoms on function and health between patients with COPD and CHF in primary health care (PHC).

Method

The study is cross sectional, including patients with COPD (n=437) and CHF (n=388), registered in the patient administrative systems of PHC. The patients received specific questionnaires – the Memorial Symptom Assessment Scale, the Medical Research Council dyspnea scale, and the Fatigue Impact Scale – by mail and additional questions about psychological and physical health.

Results

The mean age was 70±10 years and 78±10 years for patients with COPD and CHF respectively (P=0.001). Patients with COPD (n=273) experienced more symptoms (11±7.5) than the CHF patients (n=211) (10±7.6). The most prevalent symptoms for patients with COPD were dyspnea, cough, and lack of energy. For patients with CHF, the most prevalent symptoms were dyspnea, lack of energy, and difficulty sleeping. Experience of dyspnea, cough, dry mouth, feeling irritable, worrying, and problems with sexual interest or activity were more common in patients with COPD while the experience of swelling of arms or legs was more common among patients with CHF. When controlling for background characteristics, there were no differences regarding feeling irritable, worrying, and sexual problems. There were no differences in impact of symptoms or health.

Conclusion

Patients with COPD and CHF seem to experience similar symptoms. There were no differences in how the patients perceived their functioning according to their cardinal symptoms; dyspnea and fatigue, and health. An intervention for both groups of patients to optimize the management of symptoms and improve function is probably more relevant in PHC than focusing on separate diagnosis groups.

The Saudi Guidelines for the Diagnosis and Management of COPD

The Saudi Thoracic Society (STS) launched the Saudi Initiative for Chronic Airway Diseases (SICAD) to develop a guideline for the diagnosis and management of chronic obstructive pulmonary disease (COPD). This guideline is primarily aimed for internists and general practitioners. Though there is scanty epidemiological data related to COPD, the SICAD panel believes that COPD prevalence is increasing in Saudi Arabia due to increasing prevalence of tobacco smoking among men and women. To overcome the issue of underutilization of spirometry for diagnosing COPD, handheld spirometry is recommended to screen individuals at risk for COPD. A unique feature about this guideline is the simplified practical approach to classify COPD into three classes based on the symptoms as per COPD Assessment Test (CAT) and the risk of exacerbations and hospitalization. Those patients with low risk of exacerbation (<2 in the past year) can be classified as either Class I when they have less symptoms (CAT < 10) or Class II when they have more symptoms (CAT ≥ 10). High-risk COPD patients, as manifested with ≥2 exacerbation or hospitalization in the past year irrespective of the baseline symptoms, are classified as Class III. Class I and II patients require bronchodilators for symptom relief, while Class III patients are recommended to use medications that reduce the risks of exacerbations. The guideline recommends screening for co-morbidities and suggests a comprehensive management approach including pulmonary rehabilitation for those with a CAT score ≥10. The article also discusses the diagnosis and management of acute exacerbations in COPD.