Evidence of lower oxidative stress in the air spaces of patients with reversible COPD

Involvement of NK Cells against Tumors and Parasites

Host resistance against pathogens depends on a complex interplay of innate and adaptive immune mechanisms. Acting as an early line of defence, the immune system includes activation of neutrophils, tissue macrophages, monocytes, dendritic cells, eosinophils and natural killer (NK) cells. NK cells are lymphoid cells that can be activated without previous stimulation and are therefore like macrophages in the first line of defence against tumor cells and a diverse range of pathogens. NK cells mediate significant activity and produce high levels of proinflammatory cytokines in response to infection. Their cytotoxicity production is induced principally by monocyte-, macrophage- and dendritic cell-derived cytokines, but their activation is also believed to be cytokine-mediated. Recognition of infection by NK cells is accomplished by numerous activating and inhibitory receptors on the NK cells’ surface that selectively trigger the cytolytic activity in a major histocompability complex-independent manner. NK cells have trypanocidal activity of fibroblast cells and mediate direct destruction of extracellular epimastigote and trypomastigote forms of T. cruzi and T. lewisi in vitro; moreover, they kill plasmodia-infected erythrocytes directly through cell-cell interaction. This review provides a more detailed analysis of how NK cells recognize and respond to parasites and how they mediate cytotoxicity against tumor cells. Also the unique role of NK cells in innate immunity to infection and the relationship between parasites and carcinogenesis are discussed.

Inflammation, Oxidative Stress and Systemic Effects in Mild Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary diseases (COPD) is a pulmonary disease characterized by systemic abnormalities. The aim of this study is to investigate inflammation and systemic effects in mild COPD. Twenty-seven mild stable smoking related COPD patients and 15 age-matched healthy subjects were enrolled in the study. IL-6, TNF-α and IL-4 in plasma, sputum and exhaled breath condensate were measured. We also measured exhaled nitric oxide (NO) and pH in sputum and in breath condensate. Moreover, fat-free mass, body mass index (BMI), respiratory muscle strength, plasma oxidative stress and C-reactive protein (CRP) were measured. Higher concentrations were found of CRP, of diacron reactive oxygen metabolites (DROMs) and of IL-6, TNF-α and IL-4 either in plasma or in supernatant of induced sputum or in exhaled breath condensate of COPD subjects compared to healthy controls. Furthermore, higher concentrations were observed of exhaled NO and lower exhaled pH in breath condensate of COPD when compared with healthy subjects. In the group of COPD patients, the subjects with airway reversibility showed an increase of sputum eosinophils and exhaled NO, whereas the subjects without airway obstruction reversibility showed an increase in sputum neutrophils, TNF-α and IL-6. We also found a trend towards a decrease in fat-free mass and respiratory muscle strength in COPD compared to healthy subjects and a negative correlation between these systemic indices (fat-free mass, maximal inspiratory pressure, maximal expiratory pressure) and TNF-α concentrations in the blood, sputum and breath condensate. We conclude that mild COPD subjects present an increase in inflammatory markers in blood and in airways of similar pattern and furthermore, the neutrophilic pattern of airway inflammation observed in the group of COPD subjects without an airway obstruction reversibility makes it more likely that systemic features are present.

Glutathione and nitrite levels in induced sputum at COPD patients and healthy smokers

OBJECTIVES

The role of oxidative stress at the pathogenesis of chronic obstructive pulmonary disease (COPD) is known. The aim of this study is to investigate the oxidative stress with sputum induction that is a simple method in COPD patients and healthy smokers.

METHODS

Sputum induction was performed in 21 COPD patients (10 stable, 11 acute exacerbations), nine healthy smokers, and ten healthy non-smokers. Glutathione, NO2 (-) levels, and cell counts at sputum, and plasma NO2 (-) contents were evaluated in all subjects.

RESULTS

Mean sputum glutathione and NO2 (-) levels were significantly higher in acute exacerbations with COPD patients than healthy smokers (P=0.007 and P<0.001 respectively), and non-smokers (P<0.001 and P<0.001 respectively). On the other hand, sputum glutathione and NO2 (-) levels did not show significant differences between stable and acute exacerbations with COPD patients. Although, sputum glutathione levels were higher in stable COPD patients than healthy smokers', no statistically significant difference was established. In addition, sputum glutathione levels were significantly higher in healthy smokers than non-smokers (P<0.001).

CONCLUSIONS

As a result, we can say that oxidative stress increases not only in COPD patients but also in healthy smokers. In addition, sputum induction that is a simple method can be used to demonstrate to show oxidative stress.

Frailty syndrome is associated with altered circulating redox balance and increased markers of oxidative stress

Frailty syndrome (FS) is a condition described in aging and characterized by physical vulnerability to stress and lack of physiological reserve. In this study we aim to define whether circulating oxidative stress correlates to frailty in terms of glutathione balance and oxidative protein damage. In 62 elderly outpatients, classified as frail patients according to Fried's criteria, evaluation of reduced glutathione (GSH), oxidized glutathione (GSSG), tumor necrosis factor-alpha, malonaldehyde-(MDA) and 4-hydroxy-2,3-nonenal-(HNE) protein plasma adducts were performed. A significant increase in the GSSG was observed in patients with FS when compared to non-frail. No difference was shown in the GSH amount, suggesting a glutathione oxidation more than impairment of the synthesis. TNF-alpha, MDA- and HNE-adducts, were significantly higher in FS as compared to non-frail patients. A logistic regression model correlating FS with redox balance showed a close relationship between glutathione ratio (OR=1.8, 95% CI=1.2-2.5) and MDA adducts (OR=2.8, 95% CI=1.6-4.7) to frailty. Our findings show an association between oxidative imbalance and Frailty Syndrome. GSSG/GSH ratio and plasma protein adducts strongly predict the frailty conditions and seem to be reliable and easily measurable markers in the context of the multidimensional analysis of elderly patients.

Erdosteine enhances airway response to salbutamol in patients with mild-to-moderate COPD

Background: Oxidative stress is presumed to impair β-adenoceptor function and airway patency. Erdosteine (E), a mucomodulatory compound, has shown important antioxidant properties.

Methods: The objective was to assess the effect of antioxidant interventions on short-term airway response to salbutamol in non-reversible mild-to-moderate COPD patients. Thirty COPD patients (GOLD class 1—2), current smoker (≥10 pack/year), randomly received E 300 mg, N-acetylcysteine (NAC) 600 mg, or placebo, twice daily for ten days. Reversibility to salbutamol 200 μg was tested in baseline, after four and ten days of each treatment. ROS and 8-isoprostane blood levels were measured on the same days. Between-treatment comparison was performed by ANOVA and t-test or Wilcoxon test, and p<0.05 assumed. E enhanced FEV1 reversibility after four and ten days significantly (+5.1% and +5.0%; both p<0.01 vs. placebo), while NAC only showed a transient effect at day 4 (+3.0%, p<0.05), but not at day 10 (+1.3%, p = ns).

Results: E and NAC caused significant drops in ROS blood levels after four and ten days (p<0.001 and p<0.0001 vs. placebo). In contrast to NAC, E lowered 8-isoprostane levels substantially for ten days (p = 0.017 and p = 0.0004 vs. placebo, respectively). Only E restored significantly short-term reversibility in COPD patients previously unresponsive to β2-adrenergics.

Conclusions: This effect seems more related to the peculiar protection against lipid peroxidation rather than to the scavenging activity, which proves equal to that of NAC. E provides a sort of indirect bronchodilation through 're-sensitisation' of β 2-adrenoceptors. Once confirmed in further controlled studies, it may be useful in long-term treatment of COPD.