The aims of the present study were (1) to evaluate whether individual
aldehydes resulting from lipid peroxidation can be measured in exhaled breath condensate, (2) to assess the influence of sampling procedures on
aldehyde concentrations, and (3) to compare
aldehyde levels of patients with stable, moderate to severe,
chronic obstructive pulmonary disease with those of smoking and nonsmoking control subjects.
Aldehydes (
malondialdehyde,
hexanal,
heptanal, and
nonanal) were measured by liquid chromatography-tandem mass spectrometry in all samples and overlapping results were obtained by different sampling procedures.
Malondialdehyde (57.2 +/- 2.4 nmol/L),
hexanal (63.5 +/- 4.4 nmol/L), and
heptanal (26.6 +/- 3.9 nmol/L) were increased in patients as compared with nonsmoking control subjects (17.7 +/- 5.5 nmol/L, p < 0.0001; 14.2 +/- 3.5 nmol/L, p = 0.004; and 18.7 +/- 0.9 nmol/L, p = 0.002, respectively). Only
malondialdehyde was increased in patients compared with smoking control subjects (35.6 +/- 4.0 nmol/L, p = 0.0007). In conclusion, different classes of
aldehydes were identified in exhaled breath condensate of humans. Whereas all
aldehydes but
nonanal were lower in control subjects as compared with other groups, only
malondialdehyde distinguished smoking control subjects from patients with
chronic obstructive pulmonary disease and could be envisaged as a
biomarker potentially useful to monitor the disease and its response to
therapy.