Exhaled Aldehydes as Biomarkers for Lung Diseases: A Narrative Review

Abstract

Breath analysis provides great potential as a fast and non-invasive diagnostic tool for several diseases. Straight-chain aliphatic aldehydes were repeatedly detected in the breath of patients suffering from lung diseases using a variety of methods, such as mass spectrometry, ion mobility spectrometry, or electro-chemical sensors. Several studies found increased concentrations of exhaled aldehydes in patients suffering from lung cancer, inflammatory and infectious lung diseases, and mechanical lung injury. This article reviews the origin of exhaled straight-chain aliphatic aldehydes, available detection methods, and studies that found increased aldehyde exhalation in lung diseases.

Analysis of a Broad Range of Carbonyl Metabolites in Exhaled Breath by UHPLC-MS

“…Both 2-alkenal and 4-hydroxy-2-alkenal subgroups were predicted in exhaled breath from the peroxidation of unsaturated fatty acids . Acrolein was reported in exhaled breath condensate samples. , Elevated acrolein and MDA in exhaled breath are important indicators of oxidative stress and inflammation. − Elevated MDA, 4-HHE, and 4-HNE in exhaled breath condensates were reported as biomarkers of COPD and lung cancer. , Reviews of aldehydes in exhaled breath clearly indicate that these compounds are closely related to diseases. , Thus, quantitative analysis of unsaturated aldehydes in exhaled breath will be critical for developing a diagnostic tool for the detection of these diseases.…”

“…Most of the detected alkenals and hydroxy-alkenals in exhaled breath samples were confirmed using their standards with retention times in Table and MS 2 analyses. These unsaturated aldehydes were produced from the peroxidation of unsaturated fatty acids. ,, …”

“…43,44 Reviews of aldehydes in exhaled breath clearly indicate that these compounds are closely related to diseases. 6,7 Thus, quantitative analysis of unsaturated aldehydes in exhaled breath will be critical for developing a diagnostic tool for the detection of these diseases.…”

“…These unsaturated aldehydes were produced from the peroxidation of unsaturated fatty acids. 6,7,32 ■ CONCLUSIONS A MEMS-fabricated silicon microreactor was used to derivatize carbonyl compounds in exhaled breath and UHPLC-MS was used to analyze and identify the adducts. A very broad range of carbonyl compounds including saturated aldehydes, ketones, hydroxy-aldehydes, hydroxy-ketones, unsaturated aldehydes, and hydroxy-aldehydes were detected.…”

“…Breath analysis has received considerable interest because of its applications in noninvasive diagnosis of diseases. − Carbonyl compounds have been investigated because elevated levels of these compounds in exhaled breath (EB) are considered potential biomarkers for many types of diseases. − Some carbonyl compounds, such as 2-butanone, hydroxy-acetaldehyde, 3-hydroxy-2-butanone, 2-pentanal, 2-hexanal, 4-hydroxy-2-hexenal (4-HHE), and 4-hydroxy-2-nonenal (4-HNE), are reported to have elevated levels in exhaled breath of lung cancer patients. − Malondialdehyde (MDA) and 4-HNE in the breath have been identified as biomarkers of asthma, chronic obstructive pulmonary disease (COPD), cardiovascular disease, and bronchiectasis induced by oxidative stress and inflammation. − MDA and 4-HNE were also reported in several biological matrices including exhaled breath condensate, tissue, urine, serum, and bronchoalveolar lavage fluid . An elevated level of acrolein (propenal) has been found in the brain of Alzheimer’s disease subjects .…”