Oxidant status, iron homeostasis, and carotenoid levels of COPD patients with advanced disease and LTOT

Abstract

Background: The pathogenesis of chronic obstructive pulmonary disease (COPD) is associated with oxidative stress. Both iron (Fe) and oxygen are involved in the chemical reactions that lead to increased formation of reactive oxygen species. Oxidative reactions are prevented by antioxidants such as carotenoids. Objective: To study the differences in Fe status, carotenoid levels, healthy eating habits, and markers of inflammation and oxidative damage on proteins in subjects with severe COPD ± long-term oxygen therapy (LTOT) and lung-healthy control subjects. Methods: Sixty-six Caucasians with advanced COPD (28 with LTOT) and 47 control subjects were included. Questionnaires about general health, lifestyle, and dietary habits were answered. Lung function tests and blood sampling were performed. Results: COPD subjects (±LTOT) did not demonstrate increased oxidative damage, assessed by protein carbonylation (PC), while levels of soluble transferrin receptors (sTfRs) were slightly elevated. Soluble TfRs, which is inversely related to Fe status, was negatively associated with PC. Levels of carotenoids, total and β-cryptoxanthin, α- and β-carotenes, were significantly lower in COPD subjects, and their diet contained significantly less fruits and vegetables. Lutein correlated inversely with IL-6, lycopene correlated inversely with SAT, while β-carotene was positively associated with a Mediterranean-like diet. Conclusions: Fe could favor oxidative stress in COPD patients, suggesting a cautious use of Fe prescription to these patients. COPD subjects ate a less healthy diet than control subjects did and would, therefore, benefit by dietary counseling. COPD patients with hypoxemia are probably in particular need of a lycopene-enriched diet.

The Significance of iron deficiency and anemia in a real-life COPD cohort

“…The combined prevalence of all types of ID detected in this study was 30%, the most frequent type being CID. A few studies exploring the possible causality between COPD pathogenesis and severity to ID and/or anemia have already been published [21][22][23][24][25][26][27], but the comparison of ID frequencies is difficult as definitions vary across the available literature. Nickol et al were the first ones to investigate ID using definitions targeting absolute ID and identifying 18% to be iron-deficient [21], which is distinctly more than 9.3% of AID in our cohort.…”

Association of Carotenoid Intake with Pulmonary Function

“…Oxidative stress, an imbalance between an excess of oxidants and insufficient antioxidant resources, appears to trigger a number of inflammatory, obstructive, and fibrotic lung disorders and contributes to the development of COPD (15). This imbalance is known to play an important role in the pathogenesis of the disease through direct injurious effects, and by involvement in the molecular mechanisms that control lung inflammation (16).…”

“…Reactive oxygen species (ROS), such as superoxide anion, hydrogen peroxide, and hydroxyl radicals (17), are generated by inflammatory cells in the lung in response to different stimuli, including tobacco smoke (15). Past studies have found that large numbers of neutrophils and macrophages in the lungs of COPD patients generate ROS in excess such that these patients have higher levels of superoxide anion and hydrogen peroxide release (17).…”

“…This study involved 66 Caucasians with advanced COPD and 47 healthy control subjects. Overall health, lifestyle, and dietary habits were asked in questionnaires, and lung function tests and blood sampling were performed in both groups (15). Results showed that COPD subjects had significantly lower plasma levels of β-cryptoxanthin, α-and β-carotenes, and ate significantly less fruits and vegetables in their diet compared to the control group (p<0.05) (15).…”

“…Overall health, lifestyle, and dietary habits were asked in questionnaires, and lung function tests and blood sampling were performed in both groups (15). Results showed that COPD subjects had significantly lower plasma levels of β-cryptoxanthin, α-and β-carotenes, and ate significantly less fruits and vegetables in their diet compared to the control group (p<0.05) (15). The study also found that a diet with high consumption of fruits, vegetables, whole grains, polyunsaturated fatty acids, nuts, and long-chain omega-3 fats and low consumption of red and processed meat, refined grains, and sugar-sweetened drinks was associated with a lower risk of COPD (15).…”