1.
Long-term administration of N-acetylcysteine decreases hydrogen peroxide exhalation in subjects with chronic obstructive pulmonary disease.
Kasielski, M, Nowak, D
Respiratory medicine. 2001;(6):448-56
Abstract
Patients with chronic obstructive pulmonary disease (COPD) exhale more hydrogen peroxide (H2O2) and lipid peroxidation products than healthy subjects. This may reflect oxidative stress in the airways that plays important role in the development and progression of COPD. N-acetylcysteine (NAC), a mucolytic drug, possesses antioxidant properties as it is a precursor of reduced glutathione that together with glutathione peroxidase may decompose H2O2 and lipid peroxides. We aimed to determine the effect of NAC, 600 mg effervescent tablets (Fluimucil), once a day for 12 months, and placebo on the concentration of H2O2 and thiobarbituric acid reactive substances (TBARs) in expired breath condensate and serum levels of two lipid peroxidation products (TBARs, lipid peroxides) in patients with COPD. The study was performed as a double-blind, double-dummy comparison between active drug and placebo in two parallel groups. Forty-four outpatients with stable COPD (22 in the NAC group and 22 in the placebo group) completed the study. Specimens of expired breath condensate and serum were collected at the randomization visit and then every 3 months over 1 year. The concentration of TBARs and H2O2 in expired breath condensate was measured spectrofluorimetrically by the thiobarbituric acid and homovanillic acid methods, respectively. Serum levels of lipid peroxides were determined spectrophotometrically after extraction with butanol and pyridine. Initially, H2O2 exhalation did not differ between the placebo and NAC groups up to 6 months of treatment. After this the significant differences were observed. After 9 and 12 months of treatment NAC group exhaled 2.3-fold (0.17+/-0.33 microM vs. 041+/-0.26 microM, P<0.04) [median 0.01 microM, quartile range (qr)=0.22 vs. median 0.15 microM, qr =0.43] and 2.6-fold (0.15+/-0.23 microM vs. 0.40+/-0.25 microN, P<0.05) median = 0.00 microM, qr = 0.23 vs. median = 0.36 microM, qr = 0.51] less H2O2 than placebo receivers, respectively. No significant effect of NAC administration on TBARs exhalation and serum levels of TBARs and lipid peroxides were noted over the whole treatment period. Also no significant associations between exhaled H2O2 and concentrations of lipid peroxidation products were noted in both treatment groups at any time-point. These results indicate that long-term oral administration of NAC attenuates H2O2 formation in the airways of COPD subjects and prove anti-oxidant action of drug. However, further studies are necessary to estimate the clinical significance of this finding.
2.
Inhaled glucocorticosteroids decrease hydrogen peroxide level in expired air condensate in asthmatic patients.
Antczak, A, Kurmanowska, Z, Kasielski, M, Nowak, D
Respiratory medicine. 2000;(5):416-21
Abstract
H2O2 is elevated in the exhaled air condensate in several inflammatory disorders of the lung, including bronchial asthma, and thus may reflect inflammatory processes in the airways. Exhaled H2O2 may be used to guide the anti-inflammatory treatment of patients with asthma. Therefore in this study we analysed the effect of inhaled glucocorticosteroid beclomethasone for 4 weeks on H2O2 level in the exhaled air condensate. Seventeen asthmatics and 10 healthy subjects were included to the study. Eleven patients were given inhaled beclomethasone and six were given placebo (3M Health Care). In all patients pulmonary function tests were performed. H2O2 in the expired air condensate was measured spectrofluorimetically (homovanillic acid method). Inhaled beclomethasone significantly decreased H2O2 in the expired air condensate in the active-treatment group, with a fall from baseline on day 1 which remained on day 43 (follow-up) (P<0.05). Exhaled H2O2 in the active-treatment group was significantly lower than that in placebo group (P<0.05). A negative correlation between H2O2 and forced expiratory volume in 1 sec (FEV1) on day 29 was observed. The decrease in exhaled H2O2 in the active-treatment group was accompanied by an improvement in pulmonary function tests results. Inhaled glucocorticoids reduce the level of H2O2 in the expired air condensate of asthmatic patients over a 4-week period and this may reflect their anti-inflammatory activity in lung diseases.