Bronchoalveolar lavage fluid (BALF) is an important diagnostic source to
investigate molecular changes occurring in lung disorders. The objective
of this study was to assess and compare the peptidomic profiles of BALF
from premature neonates with and without bronchopulmonary dysplasia (BPD).
Samples were obtained on the 3rd day of life from 34 neonates with gestational age a parts per thousand currency sign32 weeks. Two pools of samples from patients with and without BPD were analyzed by high performance liquid chromatography. Several differentially expressed peptides were collected and sequenced. Moreover, samples from single
donors were analyzed by liquid chromatography-electrospray ionization
mass spectrometry to define the molecular mass values of various
peptides and to quantify their expression. Levels of some matrix
metalloproteinases and their tissue inhibitors were also determined in
Neonates of the BPD group (N = 16) showed significantly lower mean
gestational age and birth weight with respect to the no-BPD group (N = 18; P < 0.0001). Levels of six peptides were significantly higher in BPD patients (P < 0.05). Two of them were identified as the albumin fragments 1-21 (2,428 Da) and 399-406 (956 Da). Levels of matrix
metalloproteinase-3 (MMP-3) enzyme probably involved in albumin fragment
generation were also significantly higher in the BPD group compared to
the no-BPD group (P < 0.05), whereas the levels of tissue inhibitor of
metalloproteinases-1 were significantly lower (P < 0.05). Levels of albumin fragments and MMP-3 showed a significant correlation (P < 0.05).
This study shows that proteomic techniques can be applied to investigate
the involvement of proteolytic enzymes on the airways of mechanically
ventilated premature infants.