Chronic obstructive pulmonary disease risk: does genetics hold the answer?

Persistence of emphysema following cessation of cigarette smoke exposure requires a susceptibility factor

Chronic obstructive pulmonary disease (COPD) is caused by cigarette smoke (CS) exposure but can often be progressive even in former smokers. Exposure of mice to CS for 22 wk causes emphysema, but whether emphysema persists after cessation of CS exposure is not clear. The purpose of this study was to determine whether emphysema persists in mice following a recovery period of 22 wk and whether a susceptibility factor, such as deficiency in the Bcl-2-interacting killer (Bik), is required for this persistence. Therefore, bik+/+ and bik-/- mice at 6-10 wk of age were exposed to 250 mg/m3 total particulate matter of CS or filtered air (FA) for 3 or 22 wk and were kept in FA for an additional 22 wk. Lungs were lavaged to quantify inflammatory cells, and sections were stained with hematoxylin and eosin to assess severity of emphysema. Exposure to CS for 3 wk increased the number of inflammatory cells in bik-/- mice compared with bik+/+ mice but not at 22 wk of exposure. At 22 wk of CS exposure, extent of emphysema was similar in bik+/+ and bik-/- mice. However, when mice were exposed to CS over the first 22 wk and were kept in FA for an additional 22 wk, emphysema remained similar in bik+/+ mice but was enhanced in bik-/- mice. These findings link increased inflammation with persistent emphysematous changes even after smoking cessation and demonstrate that a preexisting susceptibility condition is required to sustain enhanced emphysema that was initiated by long-term CS exposure.NEW & NOTEWORTHY Exposure of mice to cigarette smoke (CS) for 22 wk causes emphysema, but whether emphysema persists after an additional period of 6 mo after cessation of CS exposure has not been reported. In addition, the role of preexisting susceptibility in enhancing the persistence of CS-induced emphysema after exposure to CS has stopped has not been shown. The present study shows that a preexisting susceptibility must be present to enhance CS-induced emphysema after cessation of CS exposure.

Prediction and stratification of longitudinal risk for chronic obstructive pulmonary disease across smoking behaviors

Smoking is the leading risk factor for chronic obstructive pulmonary disease (COPD) worldwide, yet many people who never smoke develop COPD. We perform a longitudinal analysis of COPD in the UK Biobank to derive and validate the Socioeconomic and Environmental Risk Score which captures additive and cumulative environmental, behavioral, and socioeconomic exposure risks beyond tobacco smoking. The Socioeconomic and Environmental Risk Score is more predictive of COPD than smoking status and pack-years. Individuals in the highest decile of the risk score have a greater risk for incident COPD compared to the remaining population. Never smokers in the highest decile of exposure risk are more likely to develop COPD than previous and current smokers in the lowest decile. In general, the prediction accuracy of the Social and Environmental Risk Score is lower in non-European populations. While smoking status is often considered in screening COPD, our finding highlights the importance of other non-smoking environmental and socioeconomic variables.

Correlation Analysis of the Therapy Adherence to Long-Acting Inhalers Among Patients with Stable COPD

Purpose

Long-acting inhalers are the mainstay maintenance therapy for stable chronic obstructive pulmonary disease (COPD) management. The aim of this study was to assess adherence to inhalers among adults with COPD in China and to develop strategies to improve adherence for the next step.

Patients and Methods

A cross-sectional study was conducted among 246 adult patients with COPD using long-acting inhalers to explore different demographic characteristics, disease characteristics and medication regimens. Adherence to inhalers was assessed using the Medication Adherence Report Scale (MARS).

Results

Among the 246 patients included in the present study, 93 (37.80%) had good adherence, while 153 (62.20%) had poor adherence. From the comparison of patients with good and poor adherence, we found that the course of disease and education background had a significant effect on adherence (p < 0.05). Among the LAMA therapy group, inhaled tiotropium bromide spray (Ingelheim am Rhein, Germany) with active release technology had better adherence than inhaled tiotropium bromide powder (Ingelheim am Rhein, Germany) (p < 0.05). Moreover, COPD patients with good adherence had better pulmonary function and fewer moderate or severe exacerbations in the past year (p < 0.05).

Conclusion

The factors affecting the use of inhalers in patients with stable COPD are complicated. Medical staff should select appropriate inhalers according to the patient's disease status and duration and provide medication education to improve adherence.

Prediction and stratification of longitudinal risk for chronic obstructive pulmonary disease across smoking behaviors

Smoking is the leading risk factor for chronic obstructive pulmonary disease (COPD) worldwide, yet many people who never smoke develop COPD. We hypothesize that considering other socioeconomic and environmental factors can better predict and stratify the risk of COPD in both non-smokers and smokers. We performed longitudinal analysis of COPD in the UK Biobank to develop the Socioeconomic and Environmental Risk Score (SERS) which captures additive and cumulative environmental, behavioral, and socioeconomic exposure risks beyond tobacco smoking. We tested the ability of SERS to predict and stratify the risk of COPD in current, previous, and never smokers of European and non-European ancestries in comparison to a composite genome-wide polygenic risk score (PGS). We tested associations using Cox regression models and assessed the predictive performance of models using Harrell's C index. SERS (C index = 0.770, 95% CI 0.756 to 0.784) was more predictive of COPD than smoking status (C index = 0.738, 95% CI 0.724 to 0.752), pack-years (C index = 0.742, 95% CI 0.727 to 0.756). Compared to the remaining population, individuals in the highest decile of the SERS had hazard ratios (HR) = 7.24 (95% CI 6.51 to 8.05, P < 0.0001) for incident COPD. Never smokers in the highest decile of exposure risk were more likely to develop COPD than previous and current smokers in the lowest decile with HR=4.95 (95% CI 1.56 to 15.69, P=6.65×10-3) and 2.92 (95%CI 1.51 to 5.61, P=1.38×10-3), respectively. In general, the prediction accuracy of SERS was lower in the non-European populations compared to the European evaluation set. In addition to genetic factors, socioeconomic and environmental factors beyond smoking can predict and stratify COPD risk for both non- and smoking individuals. Smoking status is often considered in screening; other non-smoking environmental and non-genetic variables should be evaluated prospectively for their clinical utility.

De novo discovery of traits co-occurring with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of chronic lung conditions. Genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) associated with COPD and the co-occurring conditions, suggesting common biological mechanisms underlying COPD and these co-occurring conditions. To identify them, we have integrated information across different biological levels (i.e., genetic variants, lung-specific 3D genome structure, gene expression and protein-protein interactions) to build lung-specific gene regulatory and protein-protein interaction networks. We have queried these networks using disease-associated SNPs for COPD, unipolar depression and coronary artery disease. COPD-associated SNPs can control genes involved in the regulation of lung or pulmonary function, asthma, brain region volumes, cortical surface area, depressed affect, neuroticism, Parkinson's disease, white matter microstructure and smoking behaviour. We describe the regulatory connections, genes and biochemical pathways that underlay these co-occurring trait-SNP-gene associations. Collectively, our findings provide new avenues for the investigation of the underlying biology and diverse clinical presentations of COPD. In so doing, we identify a collection of genetic variants and genes that may aid COPD patient stratification and treatment.

Compound glycyrrhiza oral solution alleviates oxidative stress and inflammation by regulating SRC/MAPK pathway in chronic obstructive pulmonary disease

OBJECTIVES

Patients with chronic obstructive pulmonary disease (COPD) suffer from persistent cough and breathlessness, which can be ameliorated by the Chinese herbal medicine glycyrrhiza. Furthermore, the SRC/MAPK pathway is activated in the process of oxidative stress and inflammation, which afflict COPD progression. Thus, this research aimed at dissecting the mechanism of compound glycyrrhiza oral solution (CGOS) relieving oxidative stress and inflammation in COPD via the SRC/MAPK pathway.

METHODS

After a COPD rat model was established using lipopolysaccharide and cigarette smoke, rats underwent intragastric administration with CGOS and intratracheal injection with LV-NC and LV-SRC lentivirus into lungs. Then, pulmonary function-related indexes were evaluated, followed by analyses of arterial blood and inflammatory cell number in prepared bronchoalveolar lavage fluids. Meanwhile, the contents of oxidative stress-related indicators (malondialdehyde, 3NT, 8-Isoprostane, glutathione, NO, and SOD) in pulmonary tissues were measured, along with RT-qPCR and ELISA detection of the expression of inflammatory factors (TNF-α, IL-1β, IL-4, and IL-10). Moreover, western blot assay was utilized to assess p-SRC/SRC and p-p38/p38 ratios in pulmonary tissues.

RESULTS

CGOS treatment enhanced PaO₂ and reduced PaCO₂ in COPD rats, accompanied by declines in the number of total cells, neutrophils, and macrophages. CGOS improved pulmonary function, decreased malondialdehyde, 3NT, 8-Isoprostane, TNF-α, and IL-1β levels, and increased GSH, NO, IL-4, and IL-10 levels and SOD activity. Mechanistically, CGOS suppressed the SRC/MAPK pathway, and SRC overexpression reversed the alleviating function of CGOS in COPD rats.

CONCLUSIONS

In conclusion, CGOS might alleviate oxidative stress and inflammation in COPD rats by inhibiting the SRC/MAPK pathway.

Gut-Lung Microbiota Interaction in COPD Patients: A Literature Review

Respiratory diseases are one of the leading causes of death in the world, which is why a lot of attention has been recently paid to studying the possible mechanisms for the development of pulmonary diseases and assessing the impact on their course. The microbiota plays an important role in these processes and influences the functionality of the human immune system. Thus, alterations in the normal microflora contribute to a reduction in immunity and a more severe course of diseases. In this review, we summarized the information about gut and lung microbiota interactions with particular attention to their influence on the course of chronic obstructive pulmonary disease (COPD).

High fitness levels offset the increased risk of chronic obstructive pulmonary disease due to low socioeconomic status: A cohort study

OBJECTIVE

Evidence suggests that higher cardiorespiratory fitness (CRF) levels can offset the increased risk of adverse outcomes due to other risk factors. The impact of high CRF levels on the increased risk of chronic obstructive pulmonary disease (COPD) due to low socioeconomic status (SES) is unknown. We aimed to assess the combined effects of SES and CRF on the future risk of COPD.

METHODS

We employed a prospective cohort of 2312 Finnish men aged 42-61 years at study entry. Socioeconomic status was self-reported and CRF was objectively assessed using respiratory gas exchange analyzers. Both exposures were categorized as low and high based on median cutoffs. Multivariable-adjusted hazard ratios (HRs) with confidence intervals (CIs) were estimated.

RESULTS

During 26.0 years median follow-up, 120 COPD cases occurred. Low SES was associated with increased COPD risk and high CRF was associated with reduced COPD risk. Compared with high SES-low CRF, low SES-low CRF was associated with an increased COPD risk 2.36 (95% CI: 1.44-3.87), with no evidence of an association for low SES-high CRF and COPD risk 1.46 (95% CI:0.82-2.60).

CONCLUSION

In middle-aged Finnish men, SES and CRF are each independently associated with COPD risk. However, high CRF levels offset the increased COPD risk related to low SES.