254 matrix metalloproteinases 8 and 9 activity in pediatric patients with acute lung injury.

Introduction/Purpose Matrix metalloproteinases (MMP)-8 and -9 have been implicated in acute lung injury (ALI) in adults. Little is known about their role in pediatric ALI, particularly as the disease progresses from the acute, exudative phase to the chronic fibroproliferative phase. Methods Lower airway secretions from 26 pediatric patients (age Results Notable differences were seen in MMP-8 and MMP-9 expression profiles and regulation. Pooled samples from the first 10 days of ALI demonstrated up-regulation of MMP-8 (ALI 67 ± 24 ng/mg; 3.7-fold increase over control), and MMP-9 (ALI 599 ± 117 ng/mg; 2.6-fold increase over control), with MMP-9 activity exceeding MMP-8 (p Conclusion Our data suggest that in pediatric ALI, MMP-8 activity increases whereas MMP-9 activity decreases with disease progression. Determining whether this shifting MMP profile can be used as a marker for protracted respiratory failure or the development of the fibroproliferative stage in the pediatric population warrants further examination.