Decreased H2O2 in exhaled breath condensate during pregnancy--feasible effect of 17beta-estradiol.

Since pregnancy is known to favor systemic generation of reactive oxygen species, this study was designed to assess the levels of exhaled hydrogen peroxide (eH2O2), serum progesterone (PG), 17beta-estradiol (E2) and systemic oxidative parameters in 20 pregnant women between 15th and 28th gestation week and 23 healthy, eumenorrheic women. Exhaled breath condensate H2O2 was assessed fluorometrically with homovanillic acid. Exhaled H2O2 levels were lowered in pregnancy (median Me 0.13 microM) compared with follicular (Me 0.29 microM) or luteal phase (Me 0.26 microM; p<0.05 vs. both). The follicular H2O2 tended to exceed luteal phase. Whole blood chemiluminescence was increased approximately ten fold in pregnancy. E2 markedly decreased chemiluminescence of isolated polymorphonuclear leukocytes. In vitro ferric reducing ability of plasma and 2,2-diphenyl-1-picryl-hydrazyl scavenging assay were not affected by E2 or PG. Decreased exhaled H2O2 during pregnancy, despite of the increased oxidative capacity of peripheral phagocytes, might be ascribed to the magnitude of increased 17beta-estradiol levels.

Increased exhaled H2O2 and impaired lung function in patients undergoing bioincompatible hemodialysis.

BACKGROUND: Chronic renal failure (CRF) and hemodialysis (HD) accumulate an inflammatory milieu, contributing to increased systemic and airway oxidative stress that may lead to lung damage. OBJECTIVES: This study was designed to assess exhaled hydrogen peroxide (H2O2), lung function and whole blood chemiluminescence in HD and CRF patients and healthy controls. METHODS: The study included 59 patients (Polyamide STM or Hemophan membranes--19, cuprophane--16, hemodiafiltration--14, continuous ambulatory peritoneal dialysis--10), 16 CRF and 16 healthy controls. The assessment of lung function included FVC (forced vital capacity), FEV1 (forced expiratory volume in the first second) and DLCOc (single breath CO diffusing capacity). Exhaled H2O2 was determined fluorometrically and resting and n-formyl-methionyl-leucyl-phenylalanine (fMLP) luminol-dependent whole blood chemiluminescence (LBCL) were measured simultaneously. RESULTS: Only cuprophane HD patients presented decreased lung function (FVC 63.8+/-17.4%, FEV1 55.9+/-20.3 and DLCOc 72.1+/- 9.3 % of predicted; p<0.05 vs. controls). These patients exhaled the highest H2O2 levels in comparison to CRF (p<0.01): median 0.36 microM (range R: 0.09-0.56 microM) and controls (p<0.05): 0.17 microM (0.2-17.8 microM). These levels were not decreased during the HD session: preHD 1.25 microM (0.2-16.5 microM) and postHD 1.3 microM (0.2-17.8 microM). As a marker of systemic oxidative stress, fMLP-induced LBCL (total light emission) was increased in these patients (1570.6 aUxs/10(4) phagocytes; R: 274.2-8598.9) and in the CRF group (2389.4 aUxs /10(4) phagocytes; R: 491.5- 6184; p<0.05 vs. controls). Other patient groups did not express elevated LBCL and revealed decreased exhaled H2O2 after a session. CONCLUSIONS: An increased oxidative burden in the lungs may contribute to functional lung impairment in patients dialyzed with a cellulose membrane. Biocompatible dialysis with other modalities might reduce airway-borne oxidative stress and is not related with lung damage.

Differential effect of cigarette smoking on hydrogen peroxide and thiobarbituric acid reactive substances exhaled in patients with community acquired pneumonia.

BACKGROUND: This study was designed to investigate the effect of cigarette smoking on hydrogen peroxide (H2O2) and thiobarbituric reactive substances (TBARs) concentrations in exhaled breath condensate (EBC) in patients with community acquired pneumonia (CAP). METHODS: H2O2 and TBARs concentrations in EBC were determined with spectrofluorimetrical assays. RESULTS: Non-smoking CAP patients (n = 24) exhaled 1.4, 1.8 and 1.7 times more H2O2 than the smoking patients with CAP (n = 19) as assessed one (0.73 +/- 0.32 microM v. 0.51 +/- 0.36 microM), three (0.84 +/- 0.31 microM v. 0.47 +/- 0.24 microM) and five (0.66 +/- 0.28 microM v. 0.40 +/- 0.35 microM) days after admission (p < 0.05 in each case). Over 10 days of hospital treatment, mean level of exhaled H2O2 0.45 +/- 0.22 microM in CAP patients with smoking history was decreased if compared with 0.71 +/- 0.19 microM exhaled H2O2 in CAP group (p = 0.005). On the contrary, TBARs concentration evaluated over entire study period was increased in smoking CAP patients (median 0.02 microM, range 0-0.32 microM) compared with non-smoking group (median 0.01 microM, range 0-0.21 microM, p < 0.05). Concurrent, active smoking status was related with the decreased levels of H2O2 exhaled in breath condensate within the course of CAP but it appeared to increase levels of TBARs. CONCLUSIONS: The differential alternations of oxidative parameters in EBC with respect to the smoking status might provide evidence of increased H2O2 decomposition and enhanced generation of reactive species in airways of CAP patients.

Elevated whole blood chemiluminescence in patients with systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is accompanied by oxidative stress that in turn may accelerate endothelium degeneration and thus disease progression. We tested whether phagocytes from SSc patients release more reactive oxygen species (ROS) and whether this release correlates with some clinical parameters. METHODS: ROS production by blood phagocytes was measured with the luminol enhanced whole blood chemiluminescence (CL). Resting and N-formyl-methionyl-leucyl-phenylalanine -induced CL (fMLP-induced CL) was measured in 30 patients with SSc and 30 healthy controls matched as to age, sex, and level of cigarette smoking. RESULTS: Resting CL and fMLP-induced CL calculated per 10(4) phagocytes present in the assayed blood sample were higher in patients with systemic sclerosis than in healthy controls (median; range, 0.88; 0.47-1.39 vs. 0.73; 0.13-1.07 aU/10(4)p and 621; 293-3522 vs. 411; 289-810 aUxs/10(4)p, p<0.02). Patients treated with cyclophosphamide and/or prednisone for 11; 3-168 months did not differ in respect to CL from those that never received the medications. Similarly, no significant differences were found between patients with limited and diffuse SSc. Resting CL correlated (p<0.05) with clinically manifested interstitial lung disease (r=0.59), single breath carbon monoxide diffusing capacity (r= -0.56) and serum autoantibodies titre (r= 0.43). CONCLUSIONS: Blood phagocytes from patients with systemic sclerosis, especially from those with interstitial lung disease, generate elevated amounts of ROS as assessed with CL. This confirms the presence of systemic oxidative stress in SSc patients.

Hydrogen peroxide in expired air condensate correlates positively with early steps of peripheral neutrophil activation in asthmatic patients.

We have found an increased H2O2 level in expired air of asthmatic patients. Neutrophils from these subjects generated higher amounts of superoxide radicals after challenge with phorbol esters than those from healthy subjects which may result from an increased activity of NADPH-oxidase. The enhanced Ca2+ mobilisation in neutrophils from asthmatics could be responsible for increased production and subsequent elevated H2O2 concentration in expired breath condensate. In this study we wished to determine whether neutrophils of asthmatic patients have enhanced [Ca2+]i response after N-formyl-methionyl-leucyl-phenylalanine--fMLP challenge as compared with cells from healthy donors, and if so, does it correlate with H2O2 levels in expired air. We examined 21 patients, 10 healthy individuals as a control group (mean age 34.3 +/- 5.5, 6 males and 4 females) and 11 asthmatic subjects (mean age 38.2 +/- 7.2, 7 males and 4 females). The rise of [Ca2+]i as an early event of neutrophil activation, was measured spectrofluorimetically with Fura-2-AM. The mean H2O2 level, measured spectrofluorimetrically in the expired breath of asthmatics, was 20-fold higher than that in healthy control (0.18 +/- 0.20 vs. 0.01 +/- 0.04 microM, p < 0.05). [Ca2+]i increase after challenge by fMLP (delta [Ca2+]i) was much higher in asthmatics than in control group (205.0 +/- 44 vs. 113.0 +/- 22 nM, p < 0.05, respectively). A strong correlation was observed between H2O2 and delta [Ca2+]i and maximal velocity of increase in [Ca2+]i in asthmatics (r = 0.87, p < 0.01 and r = 0.64, p < 0.05). We conclude that elevated H2O2 level in the expired breath condensate of asthmatics can be generated by activated neutrophils in the course of mucosal inflammation observed in bronchial asthma.

Long-term administration of N-acetylcysteine decreases hydrogen peroxide exhalation in subjects with chronic obstructive pulmonary disease.

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.

Inhaled glucocorticosteroids decrease hydrogen peroxide level in expired air condensate in asthmatic patients.

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.

Exhaled hydrogen peroxide correlates with the release of reactive oxygen species by blood phagocytes in healthy subjects.

Various cells including polymorphonuclear leukocytes, alveolar macrophages and type-II pneumocytes may be a source of exhaled hydrogen peroxide (H2O2) in airways of humans. H2O2 can convert into hydroxyl radicals leading to peroxidative damage of airways structures and formation of volatile thiobarbituric acid-reactive substances (TBARs). We tested whether exhalation of H2O2 and TBARs by healthy subjects depends on reactive oxygen species generation from blood phagocytes. The expired breath condensate (EBC) and blood specimens were collected from 41 healthy, never smoked subjects (mean age 20.7 +/- 0.8 years, 18 men, 23 women) and then the EBC concentration of H2O2 and TBARs and 2 x 10(-5) M fMLP-provoked whole blood chemiluminescence response was measured. The mean concentration of H2O2 and TBARs in EBC was 0.28 +/- 0.17 and 0.04 +/- 0.13 microM with ratio of positive readings reaching 36/41 and 4/41, respectively. The chemiluminescence response to n-formyl-methionyl-leveyl-phenylalanine stimulation was obtained in all cases and the following parameters were estimated: basal chemiluminescence (bCl); peak chemiluminescence (pCl); absolute light emission (aCl); and peaktime. H2O2 levels in EBC positively correlated (Spearmann test) with bCl (r=0.41, P<0.01), pCl (r=0.47, P<0.01), aCl (r=0.49, P<0.001), peaktime (r=0.52, P<0.001) in the whole group and with bCl (r=0.56, P<0.01), pCl (r=0.67, P<0.01), aCl (r=0.66, P<0.01) in men and with aCl (r=0.41, P<0.05) and peaktime (r=0.48, P<0.05) in women. No association between exhaled TBARs and blood phagocytes activity was found. These results indicate that H2O2 exhalation in healthy never smoked subjects depends on ability of blood phagocytes to generate reactive oxygen species.

Increased content of thiobarbituric acid-reactive substances and hydrogen peroxide in the expired breath condensate of patients with stable chronic obstructive pulmonary disease: no significant effect of cigarette smoking.

The imbalance between oxidants and antioxidants is known to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cigarette smoking is the most frequent factor responsible for development of COPD by leading to oxidant overload in the lower airways, due to presence of its own oxidants and to recruitment and activation of pulmonary phagocytes. We aimed to determine whether (1) patients with stable COPD have higher thiobarbituric acid-reactive substances (TBARs, an end-product of lipid peroxidation) and H2O2 levels in expired breath condensate than healthy subjects who have never smoked; (2) COPD subjects who are current smokers exhale more TBARs and H2O2 than COPD ex-smokers and those who have never smoked; and (3) concentration of TBARs correlates with H2O2 levels in the breath condensate of COPD patients. The TBAR and H2O2 content in expired breath condensate of 17 healthy nonsmoking subjects and 44 patients (11 current smokers, 20 ex-smokers and 13 who had never smoked) with stable COPD [forced expiratory volume in 1 s (FEV1) 63.3 +/- 16.3% and FEV1 reversibility 5.2 +/- 4.3% predicted value] was measured spectrofluorimetrically by the thiobarbituric acid and homovanillic acid methods, respectively. The mean concentrations of TBARs and H2O2 in the expired breath condensate of COPD subjects were 12 (0.48-0.86 microM vs. 0.04 +/- 0.14 microM; P < 0.05) and 10 times (0.48 +/- 0.67 microM vs. 0.05 +/- 0.07 microM; P < 0.005) higher than in healthy controls. Current smokers with COPD did not exhale more H2O2 than COPD ex-smokers and those who had never smoked. TBARs levels shared only a tendency to be higher in the breath condensate of smoking COPD subjects than in that of ex-smokers (0.92 +/- 1.49 microM vs. 0.35 +/- 0.44 microM) and of COPD subjects who had never smoked (0.92 +/- 1.49 microM vs. 0.30 +/- 0.53 microM). No correlation was found between TBAR and H2O2 levels in the whole COPD group. These variables did not correlate with cigarette smoking status and the time from smoking cessation. Subjects with stable COPD exhibit increased lipid peroxidation and H2O2 generation in the airways. Current cigarette smoking does not distinguish COPD subjects with respect to TBARs and H2O2 exhalation.

Cigarette smoking does not increase hydrogen peroxide levels in expired breath condensate of patients with stable COPD.

Cigarette smoking is the most common factor responsible for the development of chronic obstructive pulmonary disease (COPD) leading to oxidant overload in the lower airways because of the presence of oxidants in cigarette smoke and recruitment and activation of pulmonary phagocytes. In this study we intended to determine whether: 1) patients with stable COPD have higher H2O2 levels in expired breath condensate than healthy nonsmoking subjects and 2) whether cigarette smoking increases H2O2 exhalation in patients with stable COPD. The H2O2 content of the expired breath condensate of 17 healthy nonsmoking subjects and 38 patients (10 current smokers, 17 exsmokers and 11 who have never smoked) with stable COPD (forced expiratory volume in one second (FEV1) 63.3 +/- 15.5% of predicted value) was measured spectrofluorimetrically (homovanillic acid method). The mean H2O2 concentration in the expired breath condensate of COPD subjects was 10-times higher than that found in healthy controls (0.55 +/- 0.69 microM versus 0.05 +/- 0.07 microM, p < 0.005). There were no significant differences between H2O2 levels found in current smokers with COPD (0.44 +/- 0.56 microM) and COPD subjects who have never smoked (0.49 +/- 0.70 microM). No correlation was found between expired H2O2 and daily cigarette consumption or cumulative cigarette consumption in current smokers or exsmokers with COPD. These findings demonstrate that subjects with stable chronic obstructive pulmonary disease exhibit increased H2O2 generation in the airways and that cigarette smoking does not increase H2O2 production.

Elevated exhalation of hydrogen peroxide in patients with systemic sclerosis.

BACKGROUND: Systemic sclerosis is accompanied by an influx of activated phagocytes into distal airways. These cells release H2O2, which may evaporate from the airways surface and be detected in expired breath condensate. We tested whether patients with systemic sclerosis exhale more H2O2 than healthy subjects and whether breath condensate H2O2 levels correlate with some clinical parameters. MATERIAL AND METHODS: H2O2 was measured fluorimetrically in the expired breath condensate of 27 patients (22 women, five men, mean age 49 +/- 13.1 years) with systemic sclerosis and 27 age- and sex- matched healthy controls. RESULTS: Exhaled H2O2 levels were 3.5-fold higher (0.88 +/- 0.62 microM vs. 0.25 +/- 0.17 microM, P < 0.001) in the patients with systemic sclerosis than in the controls. Treatment with cyclophosphamide and/or prednisone (29 +/- 50 months, range 3-168 months) did not significantly decrease H2O2 exhalation (0.78 +/- 0.50 microM, n= 10 vs. 0.94 +/- 0.67 microM, n= 17, P > 0.05). No significant difference was found between patients with limited and diffuse scleroderma (1.03 +/- 0.69 microM, n= 17 vs. 0.63 +/- 0.41 microM, n= 10, P > 0.05). H2O2 levels correlated with disease duration (r = 0.38, P < 0.05) and time from the first Raynaud's episode (r = 0.44, P < 0.05). CONCLUSIONS: Patients with systemic sclerosis exhale more H2O2 than healthy controls, suggesting involvement of reactive oxygen species in disease processes. Lack of significant intergroups differences in H2O2 levels may have resulted from the small number of patients analyzed.