Ih. Buss et al., Elevated protein carbonyls and lipid peroxidation products correlating with myeloperoxidase in tracheal aspirates from premature infants, PEDIAT RES, 47(5), 2000, pp. 640-645
The purpose of this study is to determine whether the oxidative injury mark
ers, protein carbonyls and malondialdehyde (MDA), are elevated in tracheal
aspirates from very low birth weight (<1500 g) infants; to determine whethe
r levels correlate with myeloperoxidase as a marker of neutrophil inflammat
ion; and to assess whether high levels are associated with poor respiratory
outcome. Tracheal aspirates (144 samples) were collected from 86 infants <
1500 g at times of routine auctioning. Aspirates (82 samples) from 54 infan
ts greater than or equal to 1500 g who required intubation for a variety of
diagnoses were analyzed for comparison. Analyses were performed for protei
n carbonyls by ELISA, total malondialdehyde by HPLC, and myeloperoxidase ac
tivity. Respiratory outcome was assessed as oxygen requirement at 28-d or 3
6-wk postmenstrual age, and as the number of days of oxygen requirement. Pr
otein carbonyls were significantly higher in infants <1500 g than larger in
fants, and were highest close to birth. MDA concentrations were also higher
in the earlier samples. There was a strong positive correlation between pr
otein carbonyls and myeloperoxidase, suggesting a link between protein oxid
ation and neutrophil activation. A similar but weaker correlation was seen
for MDA. Carbonyls in samples taken after steroid administration were less
than for controls with a similar age distribution. We did not see significa
nt associations between oxidant marker levels and development of chronic lu
ng disease. Our findings of higher amounts of protein and lipid oxidation p
roducts in tracheal aspirates with high myeloperoxidase activity, taken tog
ether with other studies showing a link between neutrophil accumulation and
chronic lung disease, suggest a possible contribution by neutrophil-derive
d reactive oxygen species to the injury.