Reproducibility of oxidative stress biomarkers in breath condensate: are they reliable?

Rahman, Irfan

doi:10.1183/09031936.04.00131604

Cited by 32 publications

(14 citation statements)

References 13 publications

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“…The levels of the highly volatile H 2 O 2 in EBC may be susceptible to different cooling temperatures during collection [18], circadian rhythm [19], flow dependency [20], different methods of measurement with widely varying values (even in healthy subjects) close to lower detection limits [3,17,21,22], and high chemical reactivity with salivary and exhaled compounds by which (some) H 2 O 2 is consumed over time during collection and storage [3,17,22]. Isoprostanes are relatively stable end-products of in vivo arachidonate peroxidation and are measured in EBC by immunoassay, which might be influenced by cross-reactivity with closely related substances [17].…”

Section: Discussionmentioning

confidence: 99%

Biomarker reproducibility in exhaled breath condensate collected with different condensers

Rosias¹,

Robroeks²,

Kester³

et al. 2008

European Respiratory Journal

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Optimal collection and analysis of exhaled breath condensate (EBC) are prerequisites for standardisation and reproducibility of assessments. The present study aimed to assess reproducibility of EBC volume, hydrogen peroxide (H 2 O 2 ), 8-isoprostane and cytokine measurements using different condensers, including a newly developed glass condenser.At four points in time, 30 healthy subjects performed sequential EBC collections randomly using the following four condensers: glass, silicone, EcoScreen1 (Erich Jaeger GmbH, Hoechberg, Germany) and an optimised glass condenser. In small EBC samples, H 2 O 2 was measured by spectrophotometer, 8-isoprostane by enzyme immunoassay, and cytokines by multiplexed xMAP1 technology (Luminex Corporation, Austin, TX, USA).The optimised glass condenser yielded significantly more EBC volume (median 2,025 mL, interquartile range 1,600-2,525). The reproducibility of EBC volume, yielded by the new glass condenser, was comparable with EcoScreen1 (19-20 coefficients of variation (CV)%), but was significantly better compared with silicone and glass (29-37 CV%). The new condenser was associated with significantly more detections of H 2 O 2 , 8-isoprostane, interleukin-2, -4, -5 and -13, and tumour necrosis factor-a. Isoprostane concentrations were significantly higher using the new condenser, whereas H 2 O 2 and cytokine concentrations were not. Reproducibility of biomarkers was equally variable for all condenser types.In conclusion, significantly more exhaled breath condensate volume and biomarker detections were found using the optimised glass condenser, including higher 8-isoprostane levels. However, biomarker reproducibility in exhaled breath condensate in healthy adults was not influenced by the type of condenser.

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Section: Discussionmentioning

confidence: 99%

Biomarker reproducibility in exhaled breath condensate collected with different condensers

Rosias¹,

Robroeks²,

Kester³

et al. 2008

European Respiratory Journal

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“…There are, however, a number of uncertainties with respect to the usefulness and standardisation of exhaled breath condensate [14][15][16][17]. One recent study also failed to detect 8-isoprostane in exhaled breath condensate in the majority of cigarette smokers [18]; the reasons suggested were the high dilution of all biological constituents in the breath condensate and the low sensitivity of the 8-isoprostane enzyme immunoassay (EIA) method.…”

mentioning

confidence: 97%

8-Isoprostane as a marker of oxidative stress in nonsymptomatic cigarette smokers and COPD

Kinnula¹,

Ilumets²,

Myllärniemi³

et al. 2006

European Respiratory Journal

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8-Isoprostane is a potential in vivo marker for oxidant burden, but its usefulness in induced sputum of smokers and chronic obstructive pulmonary disease (COPD) has not been investigated.The current study investigated 58 subjects comprising 11 never-smokers, 11 ex-smokers, 13 healthy current smokers and 23 COPD with stage 0-III disease (according to the Global Initiative for Chronic Obstructive Lung Disease criteria). 8-Isoprostane was determined from induced sputum by enzyme immunoassay.Sputum 8-isoprostane levels were similar in the never-smokers and ex-smokers, but were elevated in the healthy smokers compared with nonsmokers, and in those with stage I-III COPD. Sputum 8-isoprostane levels could not differentiate nonsymptomatic smokers from those with Stage 0 COPD. There was a correlation between sputum 8-isoprostane level and lung function parameters (forced expiratory volume in one second/forced vital capacity and sputum neutrophils.In conclusion, sputum 8-isoprostane levels correlate with the severity of chronic obstructive pulmonary disease. However, they do not appear to differentiate healthy smokers from those who are at risk of developing chronic obstructive pulmonary disease (Global Initiative for Chronic Obstructive Lung Disease stage 0). KEYWORDS: Chronic obstructive pulmonary disease, cigarette smoking, oxidant, sputum C hronic obstructive pulmonary disease (COPD) is generally diagnosed when lung function parameters have become significantly reduced and a major part of the lung has been damaged. The pathogenesis of COPD has been strongly associated with reactive oxygen species [1-4], although it is not known how oxidative/nitrosative stress predicts the disease progression. Several oxidant markers and ''footprints'' of oxidative/nitrosative damage have been detected in COPD lung tissue, sputum, exhaled air and exhaled breath condensate [3][4][5][6], but it has not been unequivocally resolved whether these biomarkers can be used in the early assessment of cigarette-smoke-related lung diseases, their progression or whether they relate to smoking alone.8-Epi-prostaglandinF 2a (8-isoprostane) has been suggested to be the most reliable approach to monitor oxidative stress in vivo [7,8]. Isoprostanes are formed by free-radical-catalysed lipid peroxidation of arachidonic acid and cell membrane phospholipids. Isoprostanes can also be released into the circulation, secretions and urine where levels have been found to be stable and reproducible in many experimental approaches [8,9]. Isoprostanes also have potent biological actions and therefore they may significantly contribute to the progression of oxidant-mediated lung diseases, such as COPD.Several studies have shown elevated 8-isoprostane in the exhaled breath condensate of COPD patients [10][11][12][13]. There are, however, a number of uncertainties with respect to the usefulness and standardisation of exhaled breath condensate [14][15][16][17]. One recent study also failed to detect 8-isoprostane in exhaled breath condensate in the majority o...

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“…The mean coefficient of variation over 21 days was 45% in COPD patients and 43% in healthy subjects [34]. Due to the variability of data, concern has been raised regarding the reproducibility of the colorimetric assay in the range of values found in EBC and the usefulness of this measurement for monitoring oxidative stress in the airways [15,36,63,66]. Therefore, the use of more sensitive methods is advisable for peroxide measurement and further studies are required to establish the usefulness of other methods (i.e.…”

Section: Measurements Of Mediators In Ebcmentioning

confidence: 99%

Exhaled breath condensate: methodological recommendations and unresolved questions

Ho¹,

Hunt²,

Barnes³

2005

Eur Respir J

1,155

1,315

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Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases.The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required.Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them.Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.

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Reproducibility of oxidative stress biomarkers in breath condensate: are they reliable?

Cited by 32 publications

References 13 publications

Biomarker reproducibility in exhaled breath condensate collected with different condensers

Biomarker reproducibility in exhaled breath condensate collected with different condensers

8-Isoprostane as a marker of oxidative stress in nonsymptomatic cigarette smokers and COPD

Exhaled breath condensate: methodological recommendations and unresolved questions

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