Elevated nitrite in breath condensates of children with respiratory disease

Formanek, W.; Inci, Demet; Lauener, Roger; Wildhaber, Johannes H.; Frey, Urs; Hall, Graham L.

doi:10.1183/09031936.02.00101202

Cited by 98 publications

(72 citation statements)

References 23 publications

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“…Protocols, recommendations and potential pitfalls NO 2 -and NO 3 -have been detected in EBC by using spectrophotometric assays (Griess reaction), a fluorimetric method (2,3-diaminonapthalene (DAN) reaction), chemiluminescence assays or ion chromatography followed by conductivity measurement [91][92][93][94][95][96][97][98][99][100][101][102][103][104]. The reported detection limit of the DAN assay is 0.1 mM and that of the Griess reaction is higher [91,92].…”

Section: Level Of Validationmentioning

confidence: 99%

Exhaled breath condensate: methodological recommendations and unresolved questions

Ho¹,

Hunt²,

Barnes³

2005

Eur Respir J

1,158

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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Section: Level Of Validationmentioning

confidence: 99%

Exhaled breath condensate: methodological recommendations and unresolved questions

Ho¹,

Hunt²,

Barnes³

2005

Eur Respir J

1,158

1,315

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“…Nitrite is typically detected through one of several spectrophotometric methods (Griess reaction) involving fluorimetry, chemiluminescence, or ion chromatography [15][16][17][18][19][20][21][22][23][24][25][26][27][28] . The detection limit of fluorimetric methods is 0.1 μM.…”

Section: Introductionmentioning

confidence: 99%

Toward point-of-care management of chronic respiratory conditions: Electrochemical sensing of nitrite content in exhaled breath condensate using reduced graphene oxide

et al. 2017

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We present a portable non-invasive approach for measuring indicators of inflammation and oxidative stress in the respiratory tract by quantifying a biomarker in exhaled breath condensate (EBC). We discuss the fabrication and characterization of a miniaturized electrochemical sensor for detecting nitrite content in EBC using reduced graphene oxide. The nitrite content in EBC has been demonstrated to be a promising biomarker of inflammation in the respiratory tract, particularly in asthma. We utilized the unique properties of reduced graphene oxide (rGO); specifically, the material is resilient to corrosion while exhibiting rapid electron transfer with electrolytes, thus allowing for highly sensitive electrochemical detection with minimal fouling. Our rGO sensor was housed in an electrochemical cell fabricated from polydimethyl siloxane (PDMS), which was necessary to analyze small EBC sample volumes. The sensor is capable of detecting nitrite at a low over-potential of 0.7 V with respect to an Ag/AgCl reference electrode. We characterized the performance of the sensors using standard nitrite/buffer solutions, nitrite spiked into EBC, and clinical EBC samples. The sensor demonstrated a sensitivity of 0.21 μA μM − 1 cm − 2 in the range of 20-100 μM and of 0.1 μA μM − 1 cm − 2 in the range of 100-1000 μM nitrite concentration and exhibited a low detection limit of 830 nM in the EBC matrix. To benchmark our platform, we tested our sensors using seven pre-characterized clinical EBC samples with concentrations ranging between 0.14 and 6.5 μM. This enzyme-free and label-free method of detecting biomarkers in EBC can pave the way for the development of portable breath analyzers for diagnosing and managing changes in respiratory inflammation and disease.

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“…Among many volatile as well as non-volatile molecules which have been detected in EBC, nitrite and nitrate, the stable end products of oxidative metabolism of nitric oxide, could be of importance. Increased amounts of nitrite and nitrate have been found in the EBC of patients with asthma, especially during acute exacerbations [3,4,5]. …”

Section: Introductionmentioning

confidence: 99%

Validation of Nitrite and Nitrate Measurements in Exhaled Breath Condensate

Chládková

Krčmová²,

Chládek³

et al. 2006

Respiration

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Background: Inflammatory markers in exhaled breath condensate (EBC) are investigated as a non-invasive approach to monitoring of inflammation in the respiratory tract. EBC concentrations of nitrite and nitrate, the stable end products of oxidative metabolism of nitric oxide, are increased in patients with asthma, especially during acute exacerbations. Objectives: To examine methodological aspects of nitrite and nitrate measurements in EBC such as sample collection, storage and analysis. Methods: In a randomized study, EBC was collected twice within 1 h (with and without a nose clip) in 20 healthy adults and 20 patients with well-controlled asthma and no symptoms of allergic rhinitis. Nitrite and nitrate were assayed by ionex chromatography and fluorimetrically after derivatization with diaminonaphthalene. Results: The geometric mean [exp (mean ± SD)] EBC levels of nitrite and nitrate in healthy subjects [4.3 (3.0–6.1) and 11.0 (5.3–22.7) µmol/l] and patients [4.6 (2.6–7.3) and 8.7 (3.2–23.8) µmol/l] did not differ (p = 0.13). Wearing a nose clip (p = 0.3) did not influence nitrite and nitrate concentrations. The mean intra-subject %CVs of EBC concentrations of nitrite were 26 and 21% in healthy subjects and patients, while those of nitrate achieved 49 and 88%, respectively. Conclusions: Ionex chromatography of nitrite and nitrate requires no sample pretreatment and provides comparable results as a more laborious diaminonaphthalene method. EBC samples should be kept cold (8°C) and analyzed for nitrite and nitrate within 24 h of collection or stored in the freezer and thawed preferably only once. Wearing a nose clip during EBC collection has no influence on nitrite and nitrate concentrations. Short-term repeatability of nitrite and nitrate measurements was worse compared to published data on exhaled nitric oxide.

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Elevated nitrite in breath condensates of children with respiratory disease

Cited by 98 publications

References 23 publications

Exhaled breath condensate: methodological recommendations and unresolved questions

Exhaled breath condensate: methodological recommendations and unresolved questions

Toward point-of-care management of chronic respiratory conditions: Electrochemical sensing of nitrite content in exhaled breath condensate using reduced graphene oxide

Validation of Nitrite and Nitrate Measurements in Exhaled Breath Condensate

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