Update in Chronic Obstructive Pulmonary Disease 2018

Causes of and Clinical Features Associated with Death in Tobacco Cigarette Users by Lung Function Impairment

Rationale: Cigarette smoking contributes to the risk of death through different mechanisms. Objectives: To determine how causes of and clinical features associated with death vary in tobacco cigarette users by lung function impairment. Methods: We stratified current and former tobacco cigarette users enrolled in Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) into normal spirometry, PRISm (Preserved Ratio Impaired Spirometry), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1-2 COPD, and GOLD 3-4 COPD. Deaths were identified via longitudinal follow-up and Social Security Death Index search. Causes of death were adjudicated after a review of death certificates, medical records, and next-of-kin interviews. We tested associations between baseline clinical variables and all-cause mortality using multivariable Cox proportional hazards models. Measurements and Main Results: Over a 10.1-year median follow-up, 2,200 deaths occurred among 10,132 participants (age 59.5 ± 9.0 yr; 46.6% women). Death from cardiovascular disease was most frequent in PRISm (31% of deaths). Lung cancer deaths were most frequent in GOLD 1-2 (18% of deaths vs. 9-11% in other groups). Respiratory deaths outpaced competing causes of death in GOLD 3-4, particularly when BODE index ⩾7. St. George's Respiratory Questionnaire score ⩾25 was associated with higher mortality in all groups: Hazard ratio (HR), 1.48 (1.20-1.84) normal spirometry; HR, 1.40 (1.05-1.87) PRISm; HR, 1.80 (1.49-2.17) GOLD 1-2; HR, 1.65 (1.26-2.17) GOLD 3-4. History of respiratory exacerbations was associated with higher mortality in GOLD 1-2 and GOLD 3-4, quantitative emphysema in GOLD 1-2, and airway wall thickness in PRISm and GOLD 3-4. Conclusions: Leading causes of death vary by lung function impairment in tobacco cigarette users. Worse respiratory-related quality of life is associated with all-cause mortality regardless of lung function.

Race and Sex Differences in Mortality in Individuals with Chronic Obstructive Pulmonary Disease

Rationale: Despite differences in chronic obstructive pulmonary disease (COPD) comorbidities, race- and sex-based differences in all-cause mortality and cause-specific mortality are not well described. Objectives: To examine mortality differences in COPD by race-sex and underlying mechanisms. Methods: Medicare claims were used to identify COPD among REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort participants. Mortality rates were calculated using adjudicated causes of death. Hazard ratios (HRs) for mortality comparing race-sex groups were modeled with Cox proportional hazards regression. Results: In the 2,148-member COPD subcohort, 49% were women, and 34% were Black individuals; 1,326 deaths occurred over a median 7.5 years (interquartile range, 3.9-10.5 yr) follow-up. All-cause mortality per 1,000 person-years comparing Black versus White men was 101.1 (95% confidence interval [CI], 88.3-115.8) versus 93.9 (95% CI, 86.3-102.3; P = 0.99); comparing Black versus White women, all-cause mortality per 1,000 person-years was 74.2 (95% CI, 65.0-84.8) versus 70.6 (95% CI, 63.5-78.5; P = 0.99). Cardiovascular disease (CVD) was the leading cause-specific mortality among all race-sex groups. HR for CVD and chronic lung disease mortality were nonsignificant comparing Black versus White men. HR for CVD death was higher in Black compared with White women (HR, 1.44; 95% CI, 1.06-1.95), whereas chronic lung disease death was lower (HR, 0.44; 95% CI, 0.25-0.77). These differences were attributable to higher CVD risk factor burden among Black women. Conclusions: In the REGARDS COPD cohort, there were no race-sex differences in all-cause mortality. CVD was the most common cause of death for all race-sex groups with COPD. Black women with COPD had a higher risk of CVD-related mortality than White women. CVD comorbidity management, especially among Black individuals, may improve mortality outcomes.

N-Acetylcysteine Improves Inflammatory Response in COPD Patients by Regulating Th17/Treg Balance through Hypoxia Inducible Factor-1α Pathway

Introduction

This study was aimed to investigate the effects of N-acetylcysteine (NAC) on chronic obstructive pulmonary disease (COPD) and the change of Th17/Treg cytokine imbalance. Material and Methods. A total of 121 patients with stable COPD at the stage of C or D were consecutively enrolled and randomly divided into 2 groups. Patients in the treatment group received NAC granules (0.2 g × 10 bags, 0.4 g each time, 3 times/d) for half a year. The control group was treated with the same amount of placebo therapy. The peripheral blood of the patient was collected and the cytokine, T lymphocyte subsets were detected.

Results

We found the oral administration of NAC could regulate Th17/Treg balance to resist inflammation in COPD patients. Serum testing showed that the proportion of Treg in CD4+ T cells has increased and the Th17/Treg ratio has decreased during the NAC treatment. In vitro studies, we found that NAC regulated Th17/Treg balance through Hypoxia Inducible Factor-1α pathway.

Conclusions

Our result could provide new diagnosis and treatment for elderly patients with COPD from the perspective of immunity ideas.

Decreased expression of PPARγ is associated with aortic endothelial cell apoptosis in intermittently hypoxic rats

PURPOSE

Increasing medical researche shows that endothelial dysfunction is one of the important causes of various cardiovascular diseases related to chronic intermittent hypoxia (CIH). This study aimed to identify target proteins in CIH-related vascular dysfunction.

METHODS

A comparative proteomics analysis was conducted in aortic samples of rats treated with CIH and controls with normoxia. Bioinformatics analyses were performed to determine the potential roles of major proteins. The expressions of target proteins were measured by western blotting. Cell apoptotic ratio was detected by flow cytometer.

RESULTS

A total of 3,593 proteins in aortic tissues of rats were quantified. Ninety-two upregulated proteins and 468 downregulated proteins were identified when the cutoff of fold change was set at 1.5 (CIH vs. normoxia). The results of bioinformatics analysis revealed that the differentially expressed proteins were enriched in the processes of energy metabolism and lipid metabolism. The reduced expression level of peroxisome proliferator-activated receptor γ (PPARγ) protein was identified in thoracic aortic tissues of rats with CIH by proteomics analysis and western blotting. In intermittent hypoxia-treated rat aortic endothelial cells, PPARγ protein levels were reduced, and the apoptosis rate and caspase-3 and Bax protein levels were markedly elevated. Importantly, forced expression of PPARγ by rosiglitazone in intermittent hypoxia-treated rat aortic endothelial cells not only attenuated caspase-3 and Bax protein levels but also reduced the rate of apoptosis.

CONCLUSION

PPARγ is critical in endothelial dysfunction of rats with CIH. Additional studies on these differentially expressed proteins associated with CIH-related endothelial dysfunction are necessary.