Sex Difference in Chronic Obstructive Lung Disease. Does it Matter? A Concise Review

Levels of Urinary Mercapturic Acids of Acrolein, Methacrolein, Crotonaldehyde, and Methyl Vinyl Ketone in Relationship to Chronic Obstructive Pulmonary Disease in Cigarette Smokers of the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

Cigarette smoking is an established cause of chronic obstructive pulmonary disease (COPD). Numerous studies implicate acrolein, which occurs in relatively high concentrations in cigarette smoke and reacts readily with proteins, as one causative factor for COPD in smokers. Far less is known about the possible roles in COPD of the related α,β-unsaturated carbonyl compounds of cigarette smoke crotonaldehyde, methacrolein, and methyl vinyl ketone. In the study reported here, we analyzed mercapturic acids of these α,β-unsaturated compounds in the urine of 413 confirmed cigarette smokers in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)─202 with COPD and 211 without COPD. The mercapturic acids analyzed were 3-hydroxypropyl mercapturic acid (3-HPMA) from acrolein, 3-hydroxy-1-methylpropyl mercapturic acid (HMPMA-1) from crotonaldehyde, 3-hydroxy-2-methylpropyl mercapturic acid (HMPMA-2) from methacrolein, and 3-hydroxy-3-methylpropyl mercapturic acid (HMPMA-3) from methyl vinyl ketone. In models adjusting for age, sex, race, pack years of tobacco use, and BMI, all four mercapturic acids were increased in individuals with COPD but not significantly. Stratified by the GOLD status, there were increased levels of the metabolites associated with GOLD 3-4 compared to that with GOLD 0, with the methacrolein metabolite HMPMA-2 reaching statistical significance (adjusted odds ratio 1.23 [95% CI: 1.00-1.53]). These results highlight the possible role of methacrolein, which has previously received little attention in this regard, as a causative factor in COPD in cigarette smokers.

Secular Trends of Mortality and Years of Life Lost Due to Chronic Obstructive Pulmonary Disease in Wuhan, China from 2010 to 2019: Age-Period-Cohort Analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has been an important public health issue in China. This study aimed to analyze the temporal trends in mortality and years of life lost (YLL) from COPD, and explore the effects of age, period, and cohort in Wuhan, China from 2010 to 2019.

METHODS

Data were collected from the cause of death surveillance system in Wuhan. Age-standardized mortality rate (ASMR), age-standardized YLL rate (ASYR) and the estimated annual percent changes (EAPC) were calculated to evaluate the temporal trends. The age-period-cohort (APC) model was adopted to estimate the age, period, and cohort effects.

RESULTS

From 2010 to 2019, COPD accounted for 26,051.15 deaths and 394,659.58 person years YLL in Wuhan. Recently, the death burden of COPD in Wuhan has somewhat improved, especially after 2015, with declining trends in ASMR and ASYR. Additionally, the ASMR and ASYR of COPD was higher in males. And these of males showed the overall upward trends, with EAPCs of 1.06 (0.13, 2.00) and 1.21 (0.12, 2.31), respectively, while females showed downward trends since 2010. According to APC model, the age effect of COPD increased with age, and the cohort risk ratios (RRs) followed the overall downward trends. Period RRs for the Wuhan population generally tended to rise and then fall, with females showing a clear downward trend after 2015, while period RRs for males maintained an upward trend throughout the study period.

CONCLUSIONS

Recently, the death burden from COPD in Wuhan has improved, especially after 2015, with improvements in ASMR, ASYR and period RRs. Sex differences still exist. COPD posed a greater threat to the elderly, especially males. Public health managers should continue to execute more targeted programs to lessen the death burden of COPD in Wuhan.

Vesicular and extravesicular protein analyses from the airspaces of ozone-exposed mice revealed signatures associated with mucoinflammatory lung disease

Lung epithelial lining fluid (ELF) harbors a variety of proteins that influence homeostatic and stress responses in the airspaces. Exosomes, nano-sized extracellular vesicles, contain many proteins that vary in abundance and composition based on the prevailing conditions. Ozone causes inflammatory responses in the airspaces of experimental animals and humans. However, the exosomal protein signatures contained within the ELF from ozone-exposed lung airspaces remain poorly characterized. To explore this, we hypothesized that ozone triggers the release of exosome-bound inflammatory proteins from various cells that reflect mucoobstructive lung disease. Accordingly, we repetitively exposed adult male and female C57BL/6 mice to HEPA-filtered air (air) or 0.8 ppm ozone (4 h per day) for 14 days (five consecutive days of exposure, 2 days of rest, five consecutive days of exposure, 2 days of rest, four consecutive days of exposure). Exosome-bound proteomic signatures, as well as the levels of soluble inflammatory mediators in the bronchoalveolar lavage fluid (BALF), were determined 12-16 h after the last exposure. Principal component analyses of the exosome-bound proteome revealed a clear distinction between air-exposed and ozone-exposed mice, as well as between ozone-exposed males and ozone-exposed females. In addition to 575 proteins that were enriched in both sexes upon ozone exposure, 243 and 326 proteins were enriched uniquely in ozone-exposed males and females, respectively. Ingenuity pathway analyses on enriched proteins between ozone- and air-exposed mice revealed enrichment of pro-inflammatory pathways. More specifically, macrophage activation-related proteins were enriched in exosomes from ozone-exposed mice. Cytokine analyses on the BALF revealed elevated levels of G-CSF, KC, IP-10, IL-6, and IL-5 in ozone-exposed mice. Finally, the histopathological assessment revealed significantly enhanced intracellular localization of mucoinflammatory proteins including MUC5B and FIZZ1 in ozone-exposed mice in a cell-specific manner indicating the cellular sources of the proteins that are ferried in the exosomes upon ozone-induced lung injury. Collectively, this study identified exosomal, secretory, and cell-specific proteins and biological pathways following repetitive exposure of mice to ozone.

Hepatic sexual dimorphism - implications for non-alcoholic fatty liver disease

The liver is often thought of as a single functional unit, but both its structural and functional architecture make it highly multivalent and adaptable. In any given physiological situation, the liver can maintain metabolic homeostasis, conduct appropriate inflammatory responses, carry out endobiotic and xenobiotic transformation and synthesis reactions, as well as store and release multiple bioactive molecules. Moreover, the liver is a very resilient organ. This resilience means that chronic liver diseases can go unnoticed for decades, yet culminate in life-threatening clinical complications once the adaptive capacity of the liver is overwhelmed. Non-alcoholic fatty liver disease (NAFLD) predisposes individuals to cirrhosis and increases liver-related and cardiovascular disease-related mortality. This Review discusses the accumulating evidence of sexual dimorphism in NAFLD, which is currently rarely considered in preclinical and clinical studies. Increased awareness of the mechanistic causes of hepatic sexual dimorphism could lead to improved understanding of the biological processes that are dysregulated in NAFLD, to the identification of relevant therapeutic targets and to improved risk stratification of patients with NAFLD undergoing therapeutic intervention.

Description of Participation in Daily and Social Activities for Individuals with COPD

This study described the participation in daily and social activities and the perceived barriers and facilitators to participation of individuals with chronic obstructive pulmonary disease (COPD). Individuals, recruited from outpatient clinics, responded to a survey on their participation in, and barriers and facilitators towards, 26 daily and social activities, divided into 3 categories: (1) physical activity and movement (PAM); (2) self-care; and (3) social engagement. For each activity, chi-square analyses were used to examine participation differences by individuals': quartiles of airflow obstruction [percent predicted forced expiratory volume in 1 second (FEV1%predicted)] and breathlessness burden and exacerbation risk. Of the 200 participants (47% women; mean ± standard deviation age = 68 ± 9 years), most wanted to increase their participation in PAM activities (range 21-75%) and significant differences were found in 5/10 PAM activities for individuals' breathlessness burden and exacerbation risk (e.g., more individuals than expected in group A (modified Medical Research Council breathlessness score <2 and 0-1 exacerbations in past 12 months) participated in regular exercise as much as they wanted (χ₍₉₎²=20.43, Cramer's V=.23)). Regardless of the degree of airflow obstruction or breathlessness burden and exacerbation risk, the most common barrier to participation was breathlessness (p<.001, η²_p=.86) and the most common facilitator was engaging as part of their routine (p<.001, η²_p=.75). Individuals with COPD want to increase their participation in daily and social activities but are limited by breathlessness. Strategies to alleviate breathlessness should be identified/prioritized and incorporated into individuals' daily routines to meet their self-reported participation objectives in daily and social activities.

Acute Exacerbation According to GOLD 2017 Categories in Patients with Chronic Obstructive Pulmonary Disease

INTRODUCTION

The association between GOLD categorizations and future exacerbations has not been fully investigated. This study elucidates whether the GOLD 2017 classification is associated with different future exacerbation risk in patients with chronic obstructive pulmonary disease (COPD) compared with the previous GOLD categorization. Another objective was to investigate the impacts of the symptoms and FEV1 on the predicted future exacerbation independently of previous exacerbation history.

METHODS

We analyzed patients from three prospective COPD cohorts (SNUH, KOCOSS, and KOLD) and evaluated the risk of moderate to severe exacerbation among different models, including GOLD grade (FEV1), GOLD 2011, and GOLD 2017.

RESULTS

In total, 611 COPD patients were included (36 from SNUH, 257 from KOCOSS, and 318 from KOLD). GOLD 2017 classification, excluding FEV1% for categorization criteria, showed no differences in future exacerbation risk compared with GOLD grade and GOLD 2011 based on c-statistics. Among those with no frequent exacerbation history and FEV1 ≥50%, the group with more symptoms was significantly associated with future exacerbations than the group with less symptoms. A lower FEV1 (FEV1 <50%) was not associated with a higher future exacerbation risk than a higher FEV1 (FEV1 ≥50%), regardless of prior exacerbation history and symptom group.

CONCLUSION

The GOLD 2017 classification was not different from GOLD grade and GOLD 2011 regarding the association with future exacerbation risk, and there were no significant differences in exacerbation risk according to FEV1%. This suggests that FEV1 might not be an important factor in future exacerbation risk. These results partly support the GOLD 2017 assessment tool.

Bronchiectasis in patients hospitalized with acute exacerbation of COPD in Spain: Influence on mortality, hospital stay, and hospital costs (2006-2014) according to gender

PURPOSE

The objectives of this study were to analyze the characteristics of male and female patients hospitalized with acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) during 2006-2014 according to the presence or absence of bronchiectasis and to study the factors associated with in-hospital mortality (IHM) in patients hospitalized with AE-COPD and concomitant bronchiectasis.

METHODS

We used the Spanish National Hospital Database to analyze patients admitted with AE-COPD as their primary diagnosis. Patients included in the study were stratified according to the presence or absence of bronchiectasis as their secondary diagnosis.

RESULTS

We identified 386,646 admissions for AE-COPD, of which 19,679 (5.09%) involved patients with concomitant bronchiectasis. When patients with and without bronchiectasis were compared, we observed that the incidence of infection by Pseudomonas aeruginosa was substantially higher in the former, as were the mean stay, cost, and percentage of readmissions, although IHM and comorbidity were lower. The course of patients with AE-COPD and bronchiectasis was characterized by a gradual increase in prevalence and mean age among men and no differences in prevalence or lower mean age in women. Mortality was 4.24% and 5.02% in patients with and without bronchiectasis, respectively, although significance was lost after a multivariate adjustment (OR 0.94; 95% CI, 0.88-1.01). The factors associated with IHM were older age, higher comorbidity, isolation of P. aeruginosa, mechanical ventilation and readmission.

CONCLUSIONS

The prevalence of admission with AE-COPD and bronchiectasis increased in men but not in women during the study period. In patients hospitalized with AE-COPD, we did not find differences in mortality when comparing the presence and absence of bronchiectasis. The analysis of temporal trends revealed a significant reduction in mortality from 2006 to 2014 in male patients with COPD and concomitant bronchiectasis, but not among women. It is important to consider the factors associated with IHM such as age, comorbidity, isolation of P. aeruginosa, mechanical ventilation and readmission to better identify those patients who are at greater risk of dying during hospitalization.

Sex differences impact the lung-bone inflammatory response to repetitive inhalant lipopolysaccharide exposures in mice

Skeletal health consequences associated with inflammatory diseases of the airways significantly contribute to morbidity. Sex differences have been described independently for lung and bone diseases. Repetitive inhalant exposure to lipopolysaccharide (LPS) induces bone loss and deterioration in male mice, but comparison effects in females are unknown. Using an intranasal inhalation exposure model, 8-week-old C57BL/6 male and female mice were treated daily with LPS (100 ng) or saline for 3 weeks. Bronchoalveolar lavage fluids, lung tissues, tibias, bone marrow cells, and blood were collected. LPS-induced airway neutrophil influx, interleukin (IL)-6 and neutrophil chemoattractant levels, and bronchiolar inflammation were exaggerated in male animals as compared to female mice. Trabecular bone micro-CT imaging and analysis of the proximal tibia were conducted. Inhalant LPS exposures lead to deterioration of bone quality only in male mice (not females) marked by decreased bone mineral density, bone volume/tissue volume ratio, trabecular thickness and number, and increased bone surface-to-bone volume ratio. Serum pentraxin-2 levels were modulated by sex differences and LPS exposure. In proof-of-concept studies, ovarectomized female mice demonstrated LPS-induced bone deterioration, and estradiol supplementation of ovarectomized female mice and control male mice protected against LPS-induced bone deterioration findings. Collectively, sex-specific differences exist in LPS-induced airway inflammatory consequences with significant differences found in bone quantity and quality parameters. Male mice demonstrated susceptibility to bone loss and female animals were protected, which was modulated by estrogen. Therefore, sex differences influence the biologic response in the lung-bone inflammatory axis in response to inhalant LPS exposures.

Gender difference on the knowledge, attitude, and practice of COPD diagnosis and treatment: a national, multicenter, cross-sectional survey in China

PURPOSE

To investigate the gender difference in knowledge, attitude, and practice of COPD diagnosis and treatment in China.

PATIENTS AND METHODS

A nationwide, multicenter, cross-sectional questionnaire study was carried out to investigate patients' understanding and experience of COPD between September 2007 and December 2008.

RESULTS

Two thousand and seventy-two patients were recruited from eleven centers. The final effective questionnaires were those of 1,698 cases, of which 32% were female. Women were younger, had higher body mass index, were more never smokers, and had lesser pack-years (all P<0.01). More women had under elementary education level and monthly income <1,000 RMB (about 160 USD) (all P<0.01). Women had higher ratio of FEV1/FVC (54.1±10.9 vs 50.2±11.5), FEV1% (50.0±19.1 vs 45.4±29.0), and lower short form-36 mental component summary (57.5±26.8 vs 61.3±25.0) (all P<0.01). Fewer women reported severe exacerbation (defined as an acute worsening of respiratory symptoms that results in patient's hospitalization) in the previous year (44.5% vs 51.6%, P<0.05). More women reported that they never heard of COPD before (67.0% vs 59.0%, P<0.01). Less women reported that physician had to tell them they had emphysema (50.5% vs 60.4%) or COPD (31.9% vs 37.9%). Less women had pulmonary function test (PFT) done before (65.2% vs 70.4%, P<0.05). More women reported that they would not repeat PFT annually (91.7% vs 87.6%, P<0.05) and did not know the PFT results (78.6% vs 73.1%, P<0.05). More women reported not having had pulmonary rehabilitation before (87.8% vs 83.6%, P<0.05). Fewer women reported knowing that COPD should be given combined therapy (38.3% vs 44.5%) and long-term treatment (46.1% vs 51.9%) (all P<0.05).

CONCLUSION

Male and female patients had different experiences on COPD diagnosis and treatment. Physicians should pay more attention to patients' education on COPD, especially of women.

Sex differences in large conducting airway anatomy

Airway luminal area is the major determinant of resistance to airflow in the tracheobronchial tree. Women may have smaller central conducting airways than men; however, previous evidence is confounded by an indirect assessment of airway geometry and by subjects with prior smoking history. The purpose of this study was to examine the effect of sex on airway size in healthy nonsmokers. Using low-dose high-resolution computed tomography, we retrospectively assessed airway luminal area in healthy men ( n = 51) and women ( n = 73) of varying ages (19-86 yr). Subjects with a positive smoking history, cardiopulmonary disease, or a body mass index > 40 kg/m² were excluded. Luminal areas of the trachea, right and left main bronchus, bronchus intermediate, left and right upper lobes, and the left lower lobe were analyzed at three discrete points. The luminal areas of the conducting airways were ~26%-35% smaller in women. The trachea had the largest differences in luminal area between men and women (298 ± 47 vs. 195 ± 28 mm² or 35% smaller for men and women, respectively), whereas the left lower lobe had the smallest differences (57 ± 15 vs. 42 ± 9 mm² or 26% smaller for men and women, respectively). When a subset of subjects was matched for height, the sex differences in airway luminal area persisted, with women being ~20%-30% smaller. With all subjects, there were modest relationships between height and airway luminal area ( r = 0.73-0.53, P < 0.05). Although there was considerable overlap between sexes, the luminal areas of the large conducting airways were smaller in healthy women than in men. NEW & NOTEWORTHY Previous evidence for sex differences in airway size has been confounded by indirect measures and/or cohorts with significant smoking histories or pathologies. We found that central airways in healthy women were significantly smaller (~26%-35%) than men. The significant sex-difference in airway size was attenuated (20%-30% smaller) but preserved in a subset of subjects matched for height. Over a range of ages, healthy women have smaller central airways than men.

The View of the Turkish Thoracic Society on the Report of the GOLD 2017 Global Strategy for the Diagnosis, Management, and Prevention of COPD

Since the Global Initiative for Obstructive Lung Disease (GOLD) published its first guidelines on chronic obstructive pulmonary disease (COPD) in 2001, much has changed till 2017. Previous versions of GOLD guidelines mentioned the forced expiratory volume in one second (FEV₁)-based approach for staging and treatment modalities. Since 2011, a composite multi-dimensional approach has been introduced to cover various aspects of the disease. Unfortunately, this approach was not found to be correlated with mortality as well as the FEV₁-based approach, despite the fact that it was better for estimating exacerbation rates. Although this assessment tool has been considered as a big step in personalized medicine, the system was rather complex to use in daily practice. In 2017, GOLD introduced a major revision in many aspects of the disease. This mainly includes a revised assessment tool and treatment algorithm. This new ABCD algorithm has excluded spirometry for guiding pharmacological therapy. Treatment recommendations are mainly based on symptoms and exacerbation rates. Escalation and de-escalation strategies have been proposed for the first time. The spirometric measurement has only been retained to confirm the diagnosis and lead to nonpharmacological therapies. In this report, the Turkish Thoracic Society COPD assembly aimed to summarize and give an insight to the Turkish interpretation of GOLD 2017.